User talk:Wcherowi/Archive 2

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Natural number

Please be wary of the three revert rule on Natural number. I have made a report at WP:AN3 about the IP editor. It can be easy to get caught up just reverting things, but there are better ways to deal with the issue, although they take a little longer. — Carl (CBM · talk) 21:38, 3 October 2015 (UTC)

Thanks Carl. I'm aware and I'll let it rest for the moment. I know that there are several editors who will take care of this, I just happened to be active at the moment and did get caught up in it. Bill Cherowitzo (talk) 21:47, 3 October 2015 (UTC)

I don't know how to properly edit things on pages so I apologize, but I do know MANY people confuse Natural Numbers and Whole Numbers. Whole Numbers are all the Natural Numbers plus zero, meaning the Natural Numbers DO NOT include zero. I know there are many people that will argue against this, but it's true. Otherwise, why would there be two different names for the same set. — Preceding unsigned comment added by 107.205.236.24 (talk) 02:37, 4 October 2015 (UTC)

You are assuming that the naming of things is done in a logical and forthright manner. Unfortunately this is not the case in the real world as many, many counterexamples show. The reality here is that there are some people who consider 0 to be an integer and some people who do not. There is no central authority in mathematics that can declare one definition to be correct and the other not. Authors are allowed to decide for themselves how they want to treat 0 and no one can force them to all do it the same way. I personally do not care whether 0 is considered an integer or not. There are people I respect in both camps and all I do care about is that authors make their assumptions clear. This is an encyclopedia and we should not be taking sides on issues such as this. This is the essence of WP:NPOV. As long as we are not dealing with fringe ideas, both sides of these issues need to be fairly presented. There have been several times when things that I thought were clearly true (like your belief that the Natural Numbers have to be different from the Whole Numbers) were challenged here on Wikipedia, and after my initial reaction of NO, NO, ..., NO, I have come to accept the existence of alternate views. Bill Cherowitzo (talk) 03:36, 4 October 2015 (UTC)

I just noticed that you've made some edits at Natural number and Ordinal number. These I'm afraid will all be reverted (but not by me) because you are trying to impose your point of view in articles which take a more balanced approach. If I read your comments correctly, you are doing this because you feel that your definition is correct and I'd like to make a few comments about that. First of all, correctness is not a meaningful criteria for definitions. All well formed definitions are correct. A better question to ask about a definition is, "is it useful?" When I was in grade school (and this is before the New Math hit town) I was taught, as you believe, that the Natural numbers started at 1 and the Whole numbers started with 0. That was a useful distinction at that time given the nature of mathematics and math education. Bourbaki was rewriting the foundational material and they decided that from a set-theoretic perspective, having 0 be a natural number was very useful to them. The New Math built on Bourbaki's approach and suddenly 0 as a natural number was in the math curriculum. The negative reaction to the New Math caused a lot of back pedaling and sometimes 0 was kept as a natural number and other times not. The damage however was done and the old distinction between Natural numbers and Whole numbers was mortally wounded. Then came the steady growth of Computer Science. It turns out that indexing lists and other data structures, starting at 0 made some algorithms cleaner and easier to work with. So, having 0 as a natural number was again useful to these folks. Logicians also get into the act since it is useful for them to have 0 as a natural number. On the other hand, number theorists and other pure mathematical types have not found this useful, so they have mostly remained in the "smallest natural number is 1" camp. This story I've just told, while probably not accurate in details, is certain true in broad strokes. You have questioned why the same set would be given two different names. Well, it didn't happen that way. We started with two different sets (hence two names) and sometimes one of those sets gets changed into the other (and when that happens you get one set with two names). You also say that you hope that someone will correct the situation. I hate to say it, but that is never going to happen. Those that find 0 to be a natural number useful, will never go back and the only way the situation might change in the future is that they convince everyone else to see things their way. Bill Cherowitzo (talk) 05:13, 4 October 2015 (UTC)

Talk:Ratio

You did not believe that ratios are used as decimal fraction - I googled it up for you. Now, please re-instate my changes. Mikus (talk)

Thanks for bringing back my edits. Appreciated. Mikus (talk) 01:02, 6 October 2015 (UTC)

Josephus Problem

Hello, Wcherowi,

My name is Kaiyiknip. Yesterday I added a non-inductive proof for the Josephus Problem. You removed my edit because it is unsourced. However, the non-inductive proof I posted is my original work. Will you kindly revert your edit? That being said, I am new to wikipedia, and please let me know if I should in anyway indicate original works.

Thank you! Kaiyiknip (talk) 00:59, 15 October 2015 (UTC) — Preceding unsigned comment added by Kaiyiknip (talk • contribs) 00:53, 15 October 2015 (UTC)

Dear Kaiyiknip, since you are new to Wikipedia you probably haven't discovered all the ins and outs of editing here. One of the most important policies is that there is no original work to be posted - this is explained at WP:OR. All material should be referenced in reliable secondary sources, and as editors we are only allowed to paraphrase what we find there without violating any copyright that might be in force. This restriction can be very hard for those of us who come from an academic background where original work is the expected norm, but it is essential to the way in which Wikipedia maintains its credibility. I hope that you will be able to contribute to this effort and not get discouraged by this initial set back. Bill Cherowitzo (talk) 02:51, 15 October 2015 (UTC)

Minc's conjecture

Hi, you state in permanent that Minc's conjecture is from 1967 while other sources (see Bregman-Minc inequality) say it's from 1963. Could you maybe check this? Best wishes, --Quartl (talk) 12:22, 30 October 2015 (UTC)

You're right. I've fixed it. Bill Cherowitzo (talk) 19:49, 30 October 2015 (UTC)

Thanks a lot. --Quartl (talk) 20:49, 30 October 2015 (UTC)

Googolplex

Hey there. You edited the lead par for Googolplex but got it wrong. It really is 1 followed by 10^100 zeroes. https://en.wikipedia.org/w/index.php?title=Googolplex&type=revision&diff=688527848&oldid=687939939 - 58.96.54.118 (talk) 15:27, 1 November 2015 (UTC)

or maybe I don't know how to read the edit logs very well... and it wasn't your edit. I'm not sure. 58.96.54.118 (talk) 15:29, 1 November 2015 (UTC)

You are correct, that was not my edit. I have just fixed the page (yet again!). Bill Cherowitzo (talk) 18:26, 1 November 2015 (UTC)

Library of Babel

Just wondering why you removed my edit, and put the reason as spam. The link was to an actual library of babel, which imo is pretty damn relevant. — Preceding unsigned comment added by Edtheshed (talk • contribs) 13:20, 4 November 2015 (UTC)

Since the Library of Babel is a fictional construct, your use of the word "actual" is somewhat mystifying. I admit that I use the term spam with a bit more latitude than its actual definition permits, but my intent is to indicate some violation of what Wikipedia permits in terms of external links. The site that you want to link to violates WP:ELNO in several ways. Bill Cherowitzo (talk) 18:45, 4 November 2015 (UTC)

Maybe it wouldn't be so mystifying if you had actually looked at the website I linked to. It may not be a physical library, but it literally is a digital version of the library of babel, containing every possible set of 3200 characters. And after reading through the rules, I fail to see a single rule the site violates. Which did you think it did?--Edtheshed (talk) 11:24, 5 November 2015 (UTC)

I have. The website is a sham. Rules 1 and 11 are clearly violated. The number of subsets of 3200 characters is significantly larger than the number of atoms in the known universe, so I doubt that this electronic "library" contains them all. It is a fairly simple programming trick to make this site seem like it actually works, just sophisticated enough to catch the gullible reader. The site is an amusement and does not belong on Wikipedia. Bill Cherowitzo (talk) 17:19, 5 November 2015 (UTC)

Ok, you have a better understanding of the rules than I do. I disagree that the site is a sham though. Sure it doesn't store all the pages, but uses an algorithm that determines the content of a page from the page reference, and also works the other way. And it makes no effort to lie about this either. But yes, it is for amusement. Anyway, thankyou for explaining your reasoning to me.--Edtheshed (talk) 14:46, 11 November 2015 (UTC)

ArbCom elections are now open!

Hi,
You appear to be eligible to vote in the current Arbitration Committee election. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to enact binding solutions for disputes between editors, primarily related to serious behavioural issues that the community has been unable to resolve. This includes the ability to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate, you are welcome to review the candidates' statements and submit your choices on the voting page. For the Election committee, MediaWiki message delivery (talk) 14:27, 24 November 2015 (UTC)

Problem with "permutation group" example

I made the modification on the page permutation group concerning the direction of the diagonal in one of the example. You have commented that "Left-to-right is standard terminology and direction is down unless otherwise specified." Could you provide a reference for this "standard terminology" please that I could learn about it?

By the way, if the default is left-to-right and downward than the specification of this diagonal is not incomplete, but rather the example is incorrect. For that symmetry the permutation is (24) and not (13) as in the article. The top left corner (1) stays in place.

Cs0csi (talk) 10:24, 27 November 2015 (UTC)

I apologize for making a mistake - I think a little too much turkey was involved. My statement about the conventions still holds, it is the same as when talking about diagonals in matrices. You are correct in noting that the example was incorrect and I should have caught that (maybe it was the yams). The left-to-right rising diagonal is usually called the "back" diagonal and this is the symmetry axis of the permutation (13) in the example. I am away from home at the moment and can't look up sources but elementary abstract algebra or modern geometry texts would usually have this example labeled as either "symmetries of the square" or "dihedral group". Depending on the authors, they may or may not explicitly state the convention I mentioned. Bill Cherowitzo (talk) 13:15, 27 November 2015 (UTC)

Even better than relying on conventions, I've changed the description so that it is now explicit. This is to be preferred geometrically since it doesn't depend on the orientation of the square to begin with, and one doesn't have to rely on conventions. Bill Cherowitzo (talk) 19:15, 27 November 2015 (UTC)

Thank you for the edit on the "permutation group" page, the example is now very clear and thanks as well marking my edit "good faith" when you reverted it. I really had no intention to make any vandalism in the article.

The definition of the main diagonal for the matrices as appears in its conventional, tabular representation was clear to me, but I did not know that it applies to the geometry as well. Cs0csi (talk) 18:54, 28 November 2015 (UTC)

Old query

Quick correction: in the Discrete Mathematics article, the illustration of Wikipedia in ASCII contains an error. The W should begin with 111, not 101.

Not really. This is the difference between capital W and lowercase w. The illustration was using the uppercase version. Bill Cherowitzo (talk) 13:49, 7 September 2014 (UTC)

Topology

As a mathematician I'm sure you easily understand the opening paragraphs of the topology article. Personally, I understand it the way it was before I edited it, though I think it could be more simply worded. A high school kid trying to figure out what topology was, found the introduction incomprehensible, though he read it several times before giving up. After explaining to him what he wanted to know, I made some very modest changes using what he had found helpful from my explanation, trying to use exactly the words that were already in the article, only trying to make it more approachable. I'm not wed to the changes I made. If you don't think that it improves the article, fine, but now the ball is in your court. You own this problem now, having reverted what I wrote, saying it didn't add enough to bother keeping. Please show me how you would reword it. I don't care who gets the credit. Certainly, we can agree that this article lacks the beginning foothold for someone not quite sure of the topic, so they can then go on to understand the rest of the article. You are displeased with my attempt, that is okay. Please take a look at what I proposed & show me a better way of doing it, so I can learn from your example. Gregogil (talk) 00:28, 5 January 2016 (UTC)

I don't know if you noticed, but almost immediately after reverting I did exactly that. My edit may not satisfy you, and I'm pretty sure it would not be of much help to the afore-mentioned high school student, but I think it is a little better than what was there before. I applaud your attempt to make the article more readable, but you introduced wording that I view as being inaccurate (specifically, "...defining geometric patterns...". This is "educationese" jargon, not mathematics.) One of the things that I have stressed about writing mathematics with my own students is to "know your audience". This becomes very hard to apply in the Wikipedia setting since there is no single audience that is being written to. A rule of thumb that several editors have used is to write (at least the introductory material) to a level that is about a year before the material is introduced in a course of study. This means that not all articles are going to be comprehensible to all audiences. In this instance of Topology, I would say that the intended audience should be college juniors, or even seniors. Simply put, this article is not being written for your high school student (not to disparage the student who is probably quite capable of understanding the material if it is presented in the right way.) I could get a middle schooler to understand the basics in a one-on-one situation, but I can't write an encyclopedia article at that level. Even if I tried, other editors would revert it saying that "Wikipedia is not a textbook!" I'm sure that this is not what you wanted to hear, but I don't know how else I can respond. Bill Cherowitzo (talk) 03:44, 5 January 2016 (UTC)

Spelling

The fact that you changed the spelling of linked URLS just to push this "re" bullshit is against wiki policies regarding pushing agendas... do I really have to call in the admins?

I don't know what you are talking about. I reverted your change of spelling in accordance with Wiki policy WP:ENGVAR which says that variant English spellings are not to be changed without a good reason. The British spelling on this page has been there for a while, so if there are any linked URLs to this page, then your change would have broken them (highly unlikely since the page title did not change). You can huff and puff and call in as many admins as you like. Bill Cherowitzo (talk) 17:18, 14 January 2016 (UTC)

Near-fields

I see that you reverted an edit of mine at Near-field (mathematics). Thank you for your explanation in your edit summary of why you did that. The point you made, although simple, was one that I hadn't thought of. However, is it a realistic concern? A right near field satisfies all the axioms for a left near field except for the left distributive law; if it is also a left quasifield then it satisfies the left distributive law too, so it is a left near field as well as a right one, and similarly it is both a left and a right quasifield. Thus it satisfies the given definition for planar near fields of both handednesses, and so the possibility of "switching handedness" does not cause any problem with the definition. (Obviously, the object in question is in fact a field, but that is not relevant.) The editor who uses the pseudonym "JamesBWatson" (talk) 10:32, 14 March 2016 (UTC)

Quite right, there is no problem here, but you need to be well acquainted with the objects to see that. My thinking was that we should be more explicit in this description for readers who are not familiar with non-commutative structures. Most readers would not even think of the possibility of a handedness switch, but there are cases where it does occur. I agreed with the original editor, who, after making a point about handedness, re-enforced it with this sentence. My experience has been that it is better to be a little redundant than to have something like this turn around and bite you when you least expect it. Bill Cherowitzo (talk) 18:53, 14 March 2016 (UTC)

Oval

Hi, thanks for Your edit of the article on ovoids. I wrote a similar article on ovals, too. Would You agree, if I would translate the German article and add it to the existing one ? I think they would fit together, because the view of the German article is more general, dealing especially with the infinite case, where the present English one is dealing more with the finite case. After translation You could make it smooth and decide how to arrange it in a proper way. --Ag2gaeh (talk) 20:49, 8 March 2016 (UTC)

This sounds good to me. I have always paid more attention to the finite case, so this will be a good exercise for me. Bill Cherowitzo (talk) 20:55, 8 March 2016 (UTC)

I just added the translation of the German article. Please cut, paste and rearrange the article. --Ag2gaeh (talk) 16:18, 9 March 2016 (UTC)

Hi, I saw Your great improvements of the articles. Next days, I shall adjust the pictures to the new assignments. The article Qvist's theorem is still an orphan. Please could You place in the article on ovals somewhere a hint and a link to it. Perhaps right after the definition of an oval. --Ag2gaeh (talk) 07:08, 16 March 2016 (UTC)

To infinite ovoids: A hint in English to Heise's result is at the begining of chapter 3.5 of: Francis Buekenhout: A Characterization of Semi Quadrics, Atti dei Convegni Lincei 17 (1976), S. 393-421. — Preceding unsigned comment added by Ag2gaeh (talk • contribs) 07:42, 16 March 2016 (UTC)

Thanks for those references. I will track them down as soon as I can get a referring job out of the way. I'll include Qvist's theorem on the oval page in a few minutes. As to the proof of the first half of Qvist's theorem - I was working on that late and thought that I could simplify the notation somewhat, but I forgot to look at the accompanying diagram. I hide the diagram after I realized that its labels no longer agreed with the verbal description and I was meaning to come back to this to re-insert your notation and unhide the diagram. I thought my change was a slight improvement, but not enough of one to warrant your relabeling the diagram. I won't do anything more about this until I hear back from you. Bill Cherowitzo (talk) 17:17, 16 March 2016 (UTC)

I changed pictures of Qvist's theorem. Now the definition of an Oval within should be adjusted. If there are some more problems, please let me know.--Ag2gaeh (talk) 20:10, 16 March 2016 (UTC)

Consensus for change in circle definition

You have reverted the edit I made to circle's definition saying that it is inappropriate and there was no consensus for change. Here is the reason why I made the edit. After writing the reason for the edit on the talk page (of circle), I waited for one full day for people to reply if there was a problem with the definition I gave. But no one did. And now you have reverted the edit without giving answers to the questions I asked on the talk page, the most important one being, where is a page on "Circle" for non-mathematicians? Please do give a satisfactory answer and don't say that the Circle page is a mathematics article and will remain so forever. Gameplayer10 (talk) 09:00, 16 March 2016 (UTC)

There are several reasons why editors might not respond to a talk page query and silence should not be taken for consent. If you feel that there ought to be a page on Objects that are round, you are perfectly free to create one — just don't try to hijack a mathematics article for your own ends. Bill Cherowitzo (talk) 17:30, 16 March 2016 (UTC)

Have you read the reason that I gave for the definition being mathematical? What did you find wrong in the reasoning? Gameplayer10 (talk) 01:07, 17 March 2016 (UTC)

Coplanarity

Recently, you reverted an edit of mine at Coplanarity. Thank you for your explanation in your edit summary of why you did that. Your 18:09, 14 March 2016 (UTC) edit summary had "(Reverted ...: Orthogonality is clearly not needed for this, ...)".

Coplanarity did have orthagonality in the three-vectors property (from revision of 11:44, 15 February 2005 (UTC) (the day of its creation) through revision of 05:01, 5 March 2014 (UTC)) until you removed it. Part of your 20:02, 5 March 2014 (UTC) edit removed the orthagonality portion ("and $\mathbf {a} \cdot \mathbf {b} =0$") & broke the three-vector coplanarity test.

Properties section from Coplanarity of 11:44, 15 February 2005 (UTC)

If three 3-dimensional vectors $\mathbf {a} ,\mathbf {b}$ and $\mathbf {c}$ are coplanar, and $\mathbf {a} \cdot \mathbf {b} =0$: $(\mathbf {c} \cdot \mathbf {\hat {a}} )\cdot \mathbf {\hat {a}} \ +\ (\mathbf {c} \cdot \mathbf {\hat {b}} )\cdot \mathbf {\hat {b}} \ =\ \mathbf {\hat {c}}$ Or, the vector resolutes of $\mathbf {c}$ on $\mathbf {a}$ and $\mathbf {c}$ on $\mathbf {b}$ add to give the original $\mathbf {c}$.

Example of property being broken without orthogonality:

Three vectors that are coplanar with $\mathbf {a}$ and $\mathbf {b}$ being non-orthagonal:

$\mathbf {a} =(6,0,0)$

$\mathbf {b} =(4,4,0)$

$\mathbf {c} =(2,1,0)$

Therefore,

$\mathbf {\hat {a}} =(1,0,0)$	$\mathbf {\hat {b}} =({\frac {1}{2}}{\sqrt {2}},{\frac {1}{2}}{\sqrt {2}},0)$
$(\mathbf {c} \cdot \mathbf {\hat {a}} )\mathbf {\hat {a}} =(2,0,0)$	$(\mathbf {c} \cdot \mathbf {\hat {b}} )\mathbf {\hat {b}} =(1.5,1.5,0)$

Coplanarity: $(2,0,0)+(1.5,1.5,0)=(2,1,0)$ which is $false$

which incorrectly indicates being non-coplanar

Please (undo) your 18:09, 14 March 2016 (UTC) edit to fix this.

Thank you, -- Rayhartung (talk) 03:55, 5 April 2016 (UTC)

Sorry about that. I overlooked the fact that I had reverted to an incorrect statement. When you turned the statement into an if and only if one, the implication - if the condition holds then the vectors are coplanar - is trivially true and does not require that vectors a and b be orthogonal (since c is in the plane spanned by the projections). So I jumped the gun and reverted. However, orthogonality is needed for the converse (which was the original statement) and I didn't notice that this condition was missing before your edit. I now see that the only way the condition can hold is if a and b are orthogonal, so your edit was correct in essence. The result, however, is not totally trivial, and so, does require a citation and I have not been able to find one. I'll change the incorrect statement, but you can help in locating a citation for the result. Bill Cherowitzo (talk) 22:47, 5 April 2016 (UTC)

x^y=y^x

Hello, about this edit: I agree the linked article is about special cases when $x^{y}=y^{x}$, rather than about property which holds for all x and y (and will not return the edit myself). However, compare Equation xʸ=yˣ with other items in the "See also" section - these are also "not commutativity". I believe the link might be placed in the section Commutative property#Noncommutative operations in mathematics, but this would require adding an example of exponentiation to that section, and I did not want to make that change in GA, so I added the link to "See also" section. Stannic (talk) 18:21, 14 April 2016 (UTC)

That see also section was in pretty poor shape and I have done some pruning there, but I do understand the point you are making. The problem that I see is that by leaving the link in we would be opening up Pandora's box and have to allow all the "non-commutative operations except when ..." types of statements. I don't think that that is a road we wish to go down. Links to exponential equations or real numbers might be more appropriate for this article. Bill Cherowitzo (talk) 03:46, 15 April 2016 (UTC)

Coplanarity again

Recently, you reverted an edit of mine at Coplanarity about the matrix of coordinates of points. I don't understand why. Currently the definition is false. For exemple for 3 points (that are necessarily coplanars) X = (1,0,0), Y = (0,1,0) and Z = (0,0,1) the matrix of their coordinates is of rank 3 (identity matrix). Thus they should not be coplanar regarding the current definition. Though, they are. Could you please revert this reversion. (Btw I'm new to wikipedia, thus I might have not well explained my modifications and I apologize for this) — Preceding unsigned comment added by YSalaun (talk • contribs) 09:30, 12 May 2016 (UTC)

While you have pointed out an error in the definition (rank should be at most three, not at most two) that I will fix in a moment, the reasons I reverted your edits did not involve that. The section concerned the matrix of coordinates of the points and your intention was to rephrase this in terms of vectors ... it is fine to do it that way, but that should have been done in a different section. Also, there were formatting problems in that your subscripts were written as exponents and correcting that would have required a considerable amount of work, it was easier to revert and let you try to do it again correctly. Bill Cherowitzo (talk) 17:19, 12 May 2016 (UTC)

Hello, in fact there are no correct definition using the matrix of coordinates. I can give you a counter-exemple with X = (1,0,0), Y = (0,1,0) Z = (0,0,1) and W = (1,1,1). The four points are not coplanar though the matrix rank is of 3. I will change the definition once again, trying to be more detailed. YSalaun (talk) 07:37, 13 May 2016 (UTC)

My apologies, yes you are correct. I will help with the formatting if any is needed. Bill Cherowitzo (talk) 17:53, 13 May 2016 (UTC)

Conic section

Hi Bill,
Sorry, I was obviously mistakenly believe that to the very informative analytical edited sections, also a construction (principle parallel projection) would fit well. I can understand your decision to remove my contribution. Do you see a possibility the the constructions, perhaps in a modified form, to be used in another article? An embodiment as animations, in place of a description of construction, would be no problem for me. Please excuse my English, but the school is already very far back ... With regards from Munich Petrus3743 (talk) 10:11, 21 February 2016 (UTC)

Hi Petrus,

I thought long and hard about that contribution before I reverted it. I'm afraid that my concerns about it would apply in other articles as well, so I have no suggestions for you. On the other hand, I would still like to encourage you to use your obvious skills to produce illustrations for these Wikipedia articles. A good illustration has to be more than just something that looks good and is technically accurate, it also has to make a point - turning some verbal statement into a visual one (which should be self-explanatory and not require a lot of verbal description). If you don't mind a suggestion ... the article mentions a construction by the "parallelogram method", but there is no page that corresponds to that topic. I believe that the editor who put that in was intending to write such an article but never got around to it. I think that there is such an article on the German Wikipedia. An illustration (possibly animated) of this method would be a useful addition and I could write the description to support it. If I am wrong about the existence of the German article, there are examples on our ellipse and hyperbola pages. Let me know what you think of this suggestion. Bill Cherowitzo (talk) 18:09, 21 February 2016 (UTC)

Good Morning Bill,

thank you for your courage-giving words. I had this morning an idea, I will try this today.

- Example ellipse, as an animation, with endless loop

- It arise a cone

- The tip is cut obliquely ... and Disappears

- In the plan view arise an ellipse, with principle "parallelogram method", a few strokes, Ellipse in not true size

- This ellipse is transmitted on a perpendicular to the section plane, with principle "parallelogram method"

- The finished ellipse, at actual size, you can see about 20 to 25 seconds, then the cycle repeats ...

Servus (Austrian)Petrus3743 (talk) 08:26, 22 February 2016 (UTC)

Guten Tag, (that may be the totality of my current German ability - so, don't worry about your English)

This idea looks interesting, but I would have to see it to be sure. I need to rethink the suggestion that I made above. First of all, I made a mistake in thinking that the editor who talked about the "parallelogram method" was German, actually he is Russian. There was nothing on the German Wikipedia about the parallelogram method which is most likely a Russian term translated into English. The only thing I know about this is in these animated gifs.

• 
  Ellipse
• 
  Hyperbola
• 
  Parabola

There is a reference given in the file descriptions, but it is to a Russian book. An alternative reference gives an English version, but the construction described there is not exactly what is in these illustrations. I do not yet know if this construction technique is giving an approximation or a true construction. I do know of a true (point by point) construction based on the converse of Pascal's theorem, but it requires starting with 5 points on the conic you want to construct, so I don't immediately see how to prove (using this result) that the parallelogram method actually works. It was claimed that this is an old engineering drawing technique, so I was hoping that you might recognize it under a different name perhaps. Bill Cherowitzo (talk) 23:07, 22 February 2016 (UTC)

P.S. The ellipse construction (the easiest one to analyze) gives an exact construction and I can describe the method explicitly. I can see from this that the other constructions are exact as well, but I am too tired to write down the equations at the moment. - Bill Cherowitzo (talk) 05:11, 23 February 2016 (UTC)

Hi, just a hint: The parallelogram-method ist just the Steiner generation of a parabola, hyperbola, ellipse resp. For parabola see here Parabel , for a hyperbola Hyperbel.--Ag2gaeh (talk) 08:30, 23 February 2016 (UTC)

Thanks, I should have seen that myself. I guess that getting old is taking its toll on me. I will expand the conic section page to include this material since I have already put in a short bit about the Steiner definition. Bill Cherowitzo (talk) 20:19, 23 February 2016 (UTC)

Guten Morgen (?) Bill,

Thanks for your commitment, the cooperation with you makes fun!

Yes, I have also found on a German side the parallelogram method and then the Steiner generation (Google translation tool?).

The ellipse with parallelogram method:

I suppose it is only a certain ellipse constructively represented. You've probably noticed it, the ratio of the length (L) to the height (H) of the ellipse 2/1. Here it is easy, the number of function points with the ratio L / H = 20/10 or L / H = 18/9 ...,this is generally for ellipse, parabola and hyperbola using a freely selected conic section in my opinion not so easy possible.

I'm trying at the moment the Steiner generation in the top view ... Servus Petrus3743 (talk) 11:41, 23 February 2016 (UTC)

I inserted a section on the Steiner generation of an Ellipse: here — Preceding unsigned comment added by Ag2gaeh (talk • contribs) 12:46, 23 February 2016 (UTC)

Hi Servus,

When you get a chance, you might want to consider the following. I would like a good diagram that illustrates that the cone used for finding conic sections does not have to be a "right circular cone". There is an example, due to Johannes Werner (of Nűremberg, around 1522), of using an oblique cone (with the vertex of the cone directly over a point on the circular base) to form parabolas with vertical slices. It has been suggested that this example may have influenced Albert Dűrer. I know exactly where in the article I would place such a diagram. Thanks for considering this. Bill Cherowitzo (talk) 20:19, 23 February 2016 (UTC)

Good evening Bill,

Have I understood everything correctly ?

- preferably oblique cone projected cone tip inside the base circle

* the cone tip should project to a point on the base circle (a point of the circumference)

- is the parallelogram method still wished or some other method?

* any method can be used.

- "To form parabolas with vertical slices" that I have not yet understood (my translation error?)

* the plane sections are made with vertical planes (vertical with respect to the base circle)

- as animations for ellipse, parabola and hyperbola.

* I'm not sure about animation, it depends on how difficult it is to see what is going on in the illustration.

Incidentally, Ag2gaeh ( talk). Has an especially good job done with "Steiner generation of an ellipse" (see his message) with this help I have the construction with a straight circular cone (without animation) already completed. For "to Johannes Werner (of Nuremberg, around 1522)" I will in the Internet search Petrus3743 (talk) 22:35, 23 February 2016 (UTC)

It was easiest to answer as I did, I hope you don't mind that style. The only thing I have on Johannes Werner is a reference, Libellus super viginti duobus elementis conicis, (1522), Vienna: Alantsee. I have looked at Ag2gaeh's work, it is very good, and I can understand his German better than I can understand the Google translation of it into English. Bill Cherowitzo (talk) 23:03, 23 February 2016 (UTC)

Thank you, to the extent understood everything, when the ellipse, according Steiner's parallelogram method, is ready, I'll show it to you. Servus Petrus3743 (talk) 08:29, 24 February 2016 (UTC)

PS A crucial question I have: is the base area a circle or an ellipse?Petrus3743 (talk) 08:54, 24 February 2016 (UTC)

Oblique cone circular base area, conic section ellipse using the theorem from Steiner (parallelogram method))

Oblique cone elliptical base area, conic section ellipse using the theorem from Steiner (parallelogram method)

You can now select which form of oblique cone is advantageous. The design was not difficult. With a little trick could, by simply moving a reference line, both versions are shown. The animation would be simple: only the origin of the ellipse would be animated. Regarding John Werner I have found nothing yet... greetings Petrus3743 (talk) 14:33, 24 February 2016 (UTC)

Hi,

While it doesn't matter mathematically, I think the version with the circular base is easier to understand. I do have some issues with these illustrations. The ellipse is created when the cone is sliced by a plane, and that is what the illustration should be showing. By putting in the Steiner construction lines, you are generating the ellipse without reference to the cone, so this is confusing for a reader. The other problem I have is that this oblique cone is being represented by a cross-section (which is a triangle) and the reader must be told that this is only a cross-section of a three dimensional object or else they will not understand the illustration. Is there a way to show the cone in a three dimensional representation, perhaps in an auxiliary (or inset) diagram? Bill Cherowitzo (talk) 19:41, 25 February 2016 (UTC)

Hi,

I think we need the reader with a few words to say, this view is a front view of a real oblique circular cone.

There are shown the two relevant reverences from the cone, more is not required:

1. Reference: The height of this ellipse, red line, with the aid of the cut line through the center of cut surface

2. Reference: The length of the ellipse, by projection from cone is already predetermined by the length of Schnittlinie.

I'll try the spherical cone with the cut surfaces.

I have deliberately not referred to the construction points. If you need this, it not a problem, but may make the drawing confusing.

A link to drawings by Albrecht Dürer Dürer Konstruktion Kegelschnitt

Servus Petrus3743 (talk) 22:18, 25 February 2016 (UTC)

Good day Bill,

here is the overview image with the conic sections. The cut line for the parabola is shown parallel to the inclined Mantelinie. In the construction of the parabola is the cut line perpendicular to the base area, is that okay? Please say me your suggestions for improvement. The next is the construction hyperbola with the parallelogram method. Servus Petrus3743 (talk) 16:34, 28 February 2016 (UTC)

Hi Servus,

This is very nice. I like the fact that in this view you can see that as you go from ellipses to hyperbolas you must pass through a parabola. You also get parabolas if the cutting plane is perpendicular to the base area (circle). I wonder if you can add a small vertical cutting plane near the left side of the cone to get a second parabola. This might make the diagram look too cluttered, which would be a drawback. This is an artistic decision (to include that or not) and I can't say what to do without seeing it. Again, very nice drawing. Bill Cherowitzo (talk) 17:45, 28 February 2016 (UTC)

Hi,

Thank you for your suggestion, I try it at the moment. — Preceding unsigned comment added by Petrus3743 (talk • contribs) 09:35, 29 February 2016 (UTC)

Servus Bill,

here is the new image with your suggestion. Petrus3743 (talk) 09:47, 1 March 2016 (UTC)

Now are the three images done. Please tell me again your suggestions. For the hyperbole I have used an alternative construction method. The parallelogram method would be extensive because of necessary counter cone. Please see here Steiner-Erzeugung einer Hyperbel Regards Petrus3743 (talk) 20:34, 1 March 2016 (UTC)

• 
  Oblique circular cone with conic sections
• 
  Oblique cone circular base area, conic section ellipse using the theorem from Steiner (parallelogram method)
• 
  Oblique cone circular base area, conic section parabola using the theorem from Steiner (parallelogram method)
• 
  Oblique cone circular base area, conic section hyperbola

Guten Tag,

I really like the first image. I think the extra parabola adds to the diagram without making it look too cluttered. I am concerned about the second and third images as they mix two different concepts, the construction of a conic section in the plane by use of the parallelogram method and the construction of the conic sections by slicing a three dimensional cone. In the fourth image you do what I think of as the proper way to do this, namely, the slice of the cone is transferred to give the plane view of the conic section. Unfortunately, I can't determine from the diagram alone how this transfer is done, although I do see that you are using color to help understand this. Can you tell me what the construction steps are? Thanks. Bill Cherowitzo (talk) 19:32, 2 March 2016 (UTC)

Oblique cone circular base area, conic section hyperbola

Oblique cone circular base area, conic section ellipse

Oblique cone circular base area, conic section parabola

Hi,
Here the construction with designation of the relevant points and the construction description. If you like this, I will carry out this method for ellipse and parabola ... Please tell me again your suggestions.

Construction description

1. Shared the cutting line 0P first in eight equal length sections, near the point P bisect the last segment twice more, thus are ten segments with the points 0 ... 9 on the cutting line 0P
2. Build a perpendicular on the cutting line 0P, from the point 0
3. Determine the point 0' on this perpendicular, of free choice
4. Build a perpendicular on the segment 00', from the point 0'
5. Build a perpendicular on the segment 0P, from the point P, the intersection of the both perpendiculars is the point P'
6. Build a perpendicular on the segment 0A₀, from the point 0
7. Draw a semicircle or a circular arc about B₀ with radius A₀B₀, the intersection with the perpendicular on the segment 0A₀ is 0₁
8. Transfer the segment 00₁ on the perpendicular 00', from the point 0', the intersection is 0'₁
9. Reflect the point 0'₁ to the central axis 0'P', the intersection is $0''_{1}$, thus, the first two curve points of the intended hyperbole are done
10. For the rest of the curve points of the hyperbola, repeat the steps 6. till 9. analogous.
11. Connect the adjacent curve points together, thus, the hyperbole is done.
    

Regards Petrus3743 (talk) 21:51, 3 March 2016 (UTC)

Thank you. Sorry, I've been busy the past few days at a local international film festival and haven't had much time to respond. I do understand your construction and can see that it is correct. One small suggestion. In one, or maybe two more instances, complete the drawing of the semi-circles until they meet the vertical line (tangent). This is not necessary for the construction, but it would give the reader a clearer idea of what is happening. I think that this is what should be done with the ellipse and parabola as well. Again, thanks. Bill Cherowitzo (talk) 03:37, 9 March 2016 (UTC)

Hi Bill, I have two semicircles added (tangent on surface line of the cone, possibly click on the image) and shown in color. I hope, I have understood your proposal correctly. The constructions of the ellipse and parabola, I have adapted. For a better understanding, I have both construction descriptions added. You can they be better described in english and formulate shorter. Please tell me again your suggestions.

Construction description ellipse

1. Shared the cutting line SP first in eight equal length sections, near the point P bisect the last segment twice more, thus are ten segments with the points 1 ... 9 on the cutting line SP
2. Build a perpendicular on the cutting line SP, from the point S
3. Determine the point S' on this perpendicular, of free choice
4. Build a perpendicular on the segment SS', from the point S'
5. Build a perpendicular on the segment SP, from the point P, the intersection is the point P'
6. Reflect from S'P' the points 8' and 9' to the segment 44', the intersections are the points $8''$ and $9''$
7. Draw a parallel to the segment CD, through the point 1, the intersections are the points A₁ and B₁
8. Build a perpendicular on the segment A₁B₁, from the point 1
9. Draw a semicircle or a circular arc about B₁ with radius A₁B₁, the intersection is the point 1₁
10. Transfer the segment 11₁ on the perpendicular 11', from the point 1', the intersection is the point 1'₁
11. Reflect the point 1'₁ to the central axis S'P', the intersection is $1''_{1}$, thus, the first two curve points of the intended ellipse are done
12. For the rest of the curve points of the ellipse, repeat the steps 7. till 11. analogous.
13. Connect the adjacent curve points together, thus, the ellipse is done.
    

Construction description parabola

1. Draw a parallel to the segment A₀D, from the point P, the intersection is the point P₁
2. Draw a parallel to the segment A₀P, from the point P₁, the intersection is the point 0, the both triangles A₀CP and 0DP₁ are congruent, Thus is 0B₀ = B₀C, etc.
3. Shared the parallel 0P₁ first in eight equal length sections, near the point P₁ bisect the last segment twice more, thus are ten segments with the points 0 ... 9 on this parallel
4. Lengthen the segment A₀D and determine the point 0' on this line, of free choice
5. Build a perpendicular on the segment A₀0', from the point 0'
6. Draw a parallel to the segment A₀D, from the point P₁, the intersection is the point P'
7. Build a perpendicular on the segment A₀D, from the point 0
8. Draw a semicircle or a circular arc about B₀ with radius A₀B₀, the intersection is the point 0₁
9. Transfer the segment 00₁ on the Segment A₀0', from the point 0', the intersection is the point 0'₁
10. Reflect the point 0'₁ to the central axis 0'P', the intersection is the point $0''_{1}$, thus, the first two curve points of the intended parabola are done
11. Draw a parallel to the segment A₀D, through the point 1, the intersection are the point A₁, the point B₁ and the point 1'
12. Repeat the steps 8. till 10. analogous
13. For the rest of the curve points of the parabola, repeat the steps 11. and 12. analogous
14. Connect the adjacent curve points together, thus, the hyperbole is done.

Servus Petrus3743 (talk) 19:00, 10 March 2016 (UTC)

Good day Bill,

One question: Will you use this conic sections in an article? Greetings from the "cold" Munich Petrus3743 (talk) 09:03, 20 March 2016 (UTC)

Hi Bill,

because I have long not received a response from you to my question, I suspect that the above conic sections can not be used. Greetings--Petrus3743 (talk) 09:08, 13 May 2016 (UTC)

I am sorry that I have been so quiet lately. I have gotten distracted by several other pages and have been ignoring this. I will be able to get back to conic sections shortly and plan on using some of your illustrations when I do. Thanks for being so patient. Bill Cherowitzo (talk) 04:04, 17 May 2016 (UTC)

Finite geometry

Would you please explain the issue with Finite geometry and Rational_trigonometry?

Laurusnobilis (talk) 17:16, 23 May 2016 (UTC)

I thought my edit summary was clear, but to amplify on it ... I see no real connection between finite geometries and this fringe theory and the cited paper in the rational trigonometry section is an unpublished (arXiv papers are not published and they are not not considered reliable secondary sources) paper on Ramsey graph theory. The second citation is a broken link to a conference proceedings, also not a reliable secondary source. The section on the rational trigonometry page is sketchy and does not provide any additional information on finite geometries, so I see no need to link to it. Bill Cherowitzo (talk) 04:09, 24 May 2016 (UTC)

Binary tree in Category:Binary trees

You recently reverted one of my edits, in the way Binary tree appears in Category:Data structures instead of (Category:Data structures > Category:Trees (data structures)).

Category Category:Data structures was labelled as catdiffuse.

Can you please explain your edit? Ushkin N (talk) 04:21, 24 May 2016 (UTC)

My apologies. Your edit summary threw me off ... a little too tongue-in-cheek, it made the edit look like vandalism to me rather than a serious edit. Bill Cherowitzo (talk)

Haha, I can see. It is better to see editor history when in question.

It is easy to make mistakes in the edit summary similar to edits, so it's always worth checking both - just my 2c. Ushkin N (talk) 04:35, 24 May 2016 (UTC)

Recreational mathematics

Hi Wcherowi - I see that you recently fixed an apparent vandalism problem in the article Recreational mathematics. Thanks for you watchfulness. I was wondering if you are interested in the page enough to try to fix it a bit. It is an important topic but the page is currently a bit of a hodgepodge. I recently did extensive expansion of the article Martin Gardner and would like to see this related page improved a bit. I am a fairly good writer but I need some guidance and inspiration in deciding how to improve the quality of the Recreational mathematics page. Let me know if you have any thoughts about this. Thank you. --Toploftical (talk) 23:27, 7 June 2016 (UTC)

Hi Toploftical - Spotting obvious vandalism is easy, fixing a page is hard work. I am not sure that I can contribute very much to this page. This page is going to be difficult to amend, in part because the topic is not very well defined. What makes something a mathematical recreation versus a serious mathematical topic is pretty much a matter of taste. For instance, J.J. Seidel contributed a chapter on combinatorial designs to W.W. Rouse Ball's Mathematical Recreations and Essays, but I've spent most of my career seriously studying these things. Latin squares at the level of Sudoku and Ken-Ken are clearly recreational, but the existence of sets of mutually orthogonal ones quickly turns into cutting edge mathematical research. Where do you draw the line? I'll be glad to help if I can, but at this point (besides some obvious weeding of the external links section) I don't really see where to go with this. Bill Cherowitzo (talk) 04:54, 8 June 2016 (UTC)

Hi Wcherowi - You have already helped me to focus on the issues and the problems. Yes, the line separating recreational from serious math is difficult to fix; this was an issue I had to think hard about when revising the Martin Gardner article.

I notice that in the Template:Areas of mathematics, the "Divisions" are listed as: Pure, Applied, Discrete, Computational, Meta-, and Recreational. This elevates Recreational mathematics to one of 6 presumptively equal divisions of the whole field of mathematics–an interesting but possibly unbalanced characterization. Below is WP's assessment of these "division summary" articles along with my comments.

division	Wikipedia's rating	my assessment
Pure mathematics	B Class Top Importance	well written
Applied mathematics	B Class Top Importance	well written
Discrete mathematics	B Class Top Importance	well written but overlaps the other so-called divisions
Computational mathematics	unrated	needs a lot of work; more a list than the summary of a division
Meta-mathematics	C Class Top Importance	fairly well written but needs more work
Recreational mathematics	Start Class Low Importance	not well organized or written–but should be Medium importance

I would eventually like to bring a little more consistency to all of these articles. Are they really a fair overview of all of mathematics? I am not qualified to say. But for now I am mostly interested in improving the page Recreational mathematics which I think is a bit of a mess. I am an inveterate WikiGnome and have fiddled with a lot of math pages–for example, I cleaned up and standardized the leads of all 26 Sporadic group articles. If you know of any other WP editors who are similarly inclined, put them in touch with me. I should probably sign up with WikiProject Mathematics--Toploftical (talk) 18:23, 8 June 2016 (UTC)

One problem with these divisions of mathematics is that they do not form a partition of the field. For example, I am a pure mathematician, doing discrete mathematics with some very computationally intense periods in my work, and (formerly) in an applied math department. Some of my work could be considered to be recreational, or at least that is the way I present it to non-mathematicians and I definitely think that meta-mathematics is a branch of logic and has nothing to do with mathematics. I look at these divisions ... and laugh!

You probably should join the WikiProject since it is the easiest way to get in touch with many of the regular editors who share your interests, and it is one of the few such projects that actually functions well. Bill Cherowitzo (talk) 21:30, 8 June 2016 (UTC)

Thanks for your valuable observations. They are very helpful. When I have more time I will definitely join the math wikiproject–glad to hear that it functions well.--Toploftical (talk) 15:15, 9 June 2016 (UTC)

Standardized vs. Standardised moment at Moment (mathematics)

Recently, you reverted an edit of mine at Moment (mathematics), where I changed spelling of standardised" to "standardized" ("s" to "z") for both moment and cumulant.

When looking at other Wiki pages, it appears that the spelling with "z" is used, e.g. Standardized moment, and even the Moment_(mathematics) has to change the spelling when doing cross reference in the "See also" section, using "[ [Standardized moment | Standardised moment] ]".

What is the reason that spelling using "z" in "standardized" is wrong?

Should the other Wiki pages that spells with "s" be modified?

Best regards — Preceding unsigned comment added by MortenZdk (talk • contribs) 10:01, 16 June 2016 (UTC)

Hi MortenZdk, the Wikipedia policy on variants of English spelling (WP:ENGVAR) is pretty clear. We do not change from British English spelling (with an "s") to American English spelling (with a "z") unless there is a good reason to do so (involving some national interest in the article). Individual pages can have either spelling, pretty much determined by who originated or made the major contributions to the page. The only thing we care about is being consistent on an individual page. Thus your reasons concerning the number of Google hits or the prevalence of one or the other spelling on other pages do not carry any weight in light of this policy. There is nothing "wrong" with either spelling and as editors we need to be sensitive to the fact that this is the English Wikipedia, not the American English or British English Wikipedia, and tolerate these variations. --Bill Cherowitzo (talk) 20:25, 16 June 2016 (UTC)

Hi Bill, Thanks for your elaborate answer, and I see the point. Best regards Morten — Preceding unsigned comment added by MortenZdk (talk • contribs) 06:42, 17 June 2016 (UTC)

Palindrome

Hello Wcherowi! I tried to explain that Finnish is spoken the same way as written, phonemic, that's not so in English, German or French. This is important to tell, I think. Perhaps You could write this in proper English? Risto hot sir (talk) 18:21, 25 June 2016 (UTC) And when You say "iisii", it's a palindrome, but You write it "easy" (God knows why!). Only "s" is "right". "Do geese see God" should actually be written "duu giis sii Gad". Got the point? Risto hot sir (talk) 20:05, 25 June 2016 (UTC)

I think that you are making an interesting statement about verbal palindromes and your example of "easy" would make sense to English speakers. In the example you gave of "eye", since there is only one syllable, the point you were trying to make was lost (that is, an English example of a written and verbal palindrome). A multi-syllabic example (in English) would be nice, but hard to find, I imagine; which I guess is the point being made about the differences between Finnish and English. --Bill Cherowitzo (talk) 21:20, 25 June 2016 (UTC)

Yes, they're hard to find, but are these phonetic English palindromes?: Tent net, pet's step, cod, doc!, tit's tit!, dig Id!, pill lip, spilt lips, test set!, miss SIM, sniff fins!, "tip?" - spit!, piss sip!, stiff fits?, tin knit!, Finn, if... Risto hot sir (talk) 15:33, 26 June 2016 (UTC)

Only "tit's tit" works phonetically, of these. The structure here can be used to create more of the form "noun's noun" where noun is both a phonetic and written palindrome. For example, "eye's eye" also works. The problem is coming up with something meaningful. These two examples do have drawbacks in this regard. --Bill Cherowitzo (talk) 17:46, 26 June 2016 (UTC)

However, we do have - "Dad's dad", "Mom's mom", "Pop's pop" and "Bob's bob". --Bill Cherowitzo (talk) 18:16, 26 June 2016 (UTC)

But "eye's eye" is verbally "ais ai" and "dad's dad" "däds däd"... ? "Noun" is not a palindrome written. Risto hot sir (talk) 20:07, 26 June 2016 (UTC)

Ok, then none of these work, but "Sis's sis" (not necessarily my sister!) would have the necessary pause. When I used noun above I did not mean that that word is a palindrome, I was using it in a generic sense as I needed a part of speech that could have a possessive form.--Bill Cherowitzo (talk) 22:12, 26 June 2016 (UTC)

Now, we should talk about phonemes, not phones. A human can't make the same phone twice (when exactly measured). Phonemes differentiate words' meanings (bat, cat, fat, hat etc.). So if You record "stiff fits" and play it backwards and listen: if You understand the sentence, it's phonetic enough! Finnish children learn to read easier and earlier, 'cause they don't have to think how /i/ should be written (as a, e, i or y in "easy"). I'm very happy Englishmen didn't create numbers; otherwise 77077 could be 6809 in some cases! I find this conversation very interesting! Risto hot sir (talk) 09:54, 27 June 2016 (UTC)

Mathematical reasoning

Hi, Wcherowi! I see that you are a mathematician and in this context I ask you how do you view the more or less stringent need to (partially) source statements based on followings from mathematical definitions like what is done in molality, mole fraction, apparent molar property, etc articles along the lines of WP:CALC?--5.2.200.163 (talk) 13:55, 22 July 2016 (UTC)

Transitive relations

Hello Wcherowi,

I have recently deleted the following from "Transitive Relations". "On the other hand, "is the mother of" is not a transitive relation, because if Alice is the mother of Brenda, and Brenda is the mother of Claire, then Alice is not the mother of Claire. What is more, it is anti-transitive: Alice can never be the mother of Claire." "Then again, in biology we often need to consider motherhood over an arbitrary number of generations: the relation "is a "matri-linear" ancestor of". This is a transitive relation. More precisely, it is the transitive closure of the relation "is the mother of"."

The reasons are the following: While I concede it is possible that "is greater than" is not equivalent as "is the mother of", the example that you have provided i.e. Alice, Brenda, Claire etc., is not sufficient to justify a distinction thereof.

The structure of this example is as follows: If (Alice) is (the mother of Brenda), + if (Brenda) is (the mother of Claire), then, (Alice) must be (the mother of Claire).

From the above, you argue that it is fallacious to conclude that (Alice) must be (the mother of Claire).

However, in order to argue that (Alice) is NOT (the mother of Claire), you must assume: If (the mother of Brenda) is (Brenda).

Since the above is a flawed assumption, the example that you have provided is not sufficient to justify a distinction between "is greater than" and "is the mother of".

Many thanks,

Martin — Preceding unsigned comment added by Martinren27 (talk • contribs) 17:41, 5 August 2016 (UTC)

I'm sorry but I do not follow your explanation of what you are objecting to. As in all cases where real life examples are used to model logical or mathematical situations, there are some unstated assumptions of a common sense nature that are being made. In this case I can see two such assumptions: 1) People with different names are different people, and 2) Someone can not be their own mother. Under these assumptions the argument seems clear to me, Alice can not be the mother of Claire since Alice is not Brenda. --Bill Cherowitzo (talk) 19:59, 5 August 2016 (UTC)

Consistent with what?

Regarding this diff you replaced the use of <math> tags with {{math}} with the reason "more consistent formatting" but {{math}} isn't used anywhere else in the article. The use of the tags is built into the VisualEditor so I assumed it was prefered. But I'd love to learn more. Enosh (talk) 20:06, 10 August 2016 (UTC)

Sorry, it's hard to be precise with short edit summaries. The consistency had to do with a mix of type fonts, some serif (from either of the math templates) and some sans serif (the default). Since I knew that I would edit to fix that problem I kind of reverted to my stylistic choices; {{math}} in-line and <math> for display. While things have gotten much better lately, when I started editing, <math> in-line was absolutely horrendous. As I said, things have gotten better, but I can still see vertical alignment and intensity problems and so, will remain with my choices for a little while longer. Had you caught all the variables in your edit, I probably would not have done anything, since <math> for everything seems to be the direction we are headed in.--Bill Cherowitzo (talk) 21:24, 10 August 2016 (UTC)

Palindrome

Notifying all named accounts who have edited this article this year. There is a discussion of whether this article should contain foreign language palindromes. If you would like to comment the thread is Talk:Palindrome#Non-English_palindromes_2 Meters (talk) 21:00, 3 October 2016 (UTC)

Cabal (set theory)

https://en.wikipedia.org/w/index.php?title=Cabal_%28set_theory%29&oldid=745665623

Simply revert with no explanation?

The article needs more justification. As it is, it sounds like a short-lived informal "club" or in-group or clique of researchers at a university who at one point in time happened to be studying a particular topic that happens to be rather obscure. Not even a formal fraternity. Scarcely notable. In fact, the only tangible evidence of it at all is a somewhat humorous-in-poor-taste title of the proceedings of some colloquium that was held over thirty years ago.

The papers linked in the article downloaded from JSTOR and republished at http://www.cs.umd.edu/~gasarch/ are clearly a copyright violation. 134.192.20.164 (talk) 14:46, 23 October 2016 (UTC)

The place for this discussion is on the talk page of Cabal (set theory). I was simply following the preferred Wikipedia modus operandi as explained in WP:BRD. It seemed to me that the word "Cabal" carries a lot more baggage for you than it does for me and these edits appear to be a form of attack on this article due to that baggage. I'd be happy to discuss your concerns on the appropriate talk page. Bill Cherowitzo (talk) 18:19, 23 October 2016 (UTC)

Permutation Matrix

2001:DA8:8000:E003:0:0:0:7A0C (talk) 07:42, 3 November 2016 (UTC)

Hello! I altered the section to which eigenvalue-related issue belongs, and plugged a reference, please help review my alternation, and I am willing to make it better under your advise.  :) From a sincere learner.

This was better. I've done some copyediting to improve the English. The reference however, being an arXiv paper, is not considered a reliable source (unless it was actually published somewhere) and a better reference should be found, preferably one that has the specialization that is used in the article. --Bill Cherowitzo (talk) 17:17, 3 November 2016 (UTC)

Thanks a lot! — Preceding unsigned comment added by 2001:DA8:8000:E003:0:0:0:1A57 (talk) 10:50, 5 November 2016 (UTC)