Wikipedia:Reference desk/Archives/Mathematics/2019 April 4

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April 4

Wikipedia:Reference_desk/Archives/Mathematics/2018 June 23#Bathroom tiling question...

The following question was asked twice before but was archived before answer (once after 7 hours and once after 13):

I subscribe to a faculty mathematics journal. I am reminded of a puzzle I saw there which remains the only one which nobody has submitted an answer to. Can the Wikipedia experts do better?

A year-to-view calendar has the months in a conventional arrangement of three months in each of four rows. The names of the months are printed as normal, but the days (Sunday to Saturday) and the dates (1 to 28, 29, 30, or 31 as the case may be) are printed on removable tiles. You can choose from 1x1 squares (for a single month), 1x2 rectangles (for two adjoining months in a single row) or 1x3 rectangles (covering the whole row) and both sides of the tiles are available for printing. What is the minimum number of tiles you need to print up to ensure your calendar can be used in any year?

- 86.155.146.159 16:47, 30 June 2018

Supplementary question:

Assume the tile area covered by the display for a single month to be 1 unit, irrespective of the number of tiles printed what is the minimum number of units required to ensure your calendar can be used in any year? There may be a direct relationship to the minimum number of tiles required - I don't know if there is or not. 86.130.156.147 (talk) 12:33, 17 February 2019 (UTC)

I presume that we need to work out what variations we have in months. There are obviously a set of 7 with the first of the month on each day of the week. Then there are 28, 29, 30 and 31 day months, so we need 28 (7*4) different 1x1 tile-faces (perhaps only 14 double sided tiles). But we may need multiple copies of the tiles (we will only ever need one copy of the 28 and 29 day months - February. Duplication needs thinking about, but simplistically there are 4 30-day months (sep apr jun nov) and 7 31-day months (jan mar may jul aug oct dec). Therefore 7 * (1 + 1 + 4 + 7) 1x1 tile faces = 91. Therefore 46 1x1 tiles is sufficient, but can they be reduced by mixing starting day of week within each year (yes) and by merging adjacent months into 1x2 or 1x3 tiles (yes). That last sentence needs thinking doing. But your answer is "less than 46 tiles". -- SGBailey (talk) 10:41, 3 April 2019 (UTC)

Why do you want a calendar in your bathroom?

Some years ago, when in hospital, I went to the bathroom one morning and noticed a laminated piece of paper on the floor propped against the wall. Picking it up, I saw it was a year-to-view calendar printed from the timeanddate.co.uk website. Large areas of the world don’t have access to the internet, let alone printers and laminating machines, so a calendar you don’t throw away would be extremely useful (as it would be everywhere, for environmental reasons). Lamination is also to be discouraged because it generates plastic. Can anyone estimate the total weight of calendars currently binned each year?

As for duplication, in a common year October is a duplicate of January and in a leap year there are no duplications at all.86.146.195.49 (talk) 08:19, 4 April 2019 (UTC)

I can get it down to 18 1x3 double sided tiles. 7 do Mon thru Sun, Jan thru Mar, non leap one side and leap other side. Then the remaining 9 months are 7+7+7 tilefaces which can be squeezed onto 11 tiles. -- SGBailey (talk) 08:39, 4 April 2019 (UTC)

Now, you've eliminated the need for duplicate faces because the tiles needed for January and October are separate. I would have thought, therefore, that April to December could be squeezed onto only seven tiles (Sunday to Saturday, beginning each day of the week), with a 31-day month on one side and a 30-day month on the other. Can the fronts and backs be judiciously arranged so that the tile which has a particular 31-day month on the front does not display a 30-day month on the back which is required in the same year? 86.146.195.49 (talk) 09:00, 4 April 2019 (UTC)

Hold on! Obviously you can't cover nine months with only seven tiles. Could you do January and February on their own and arrange the other eleven tiles somehow to cover March to December? 86.146.195.49 (talk) 09:05, 4 April 2019 (UTC)

hi, ive post something abt some possible solution polynomial time for discrete logarithm problem

Suposing it works well n suposing i got some other ideas that i tried also put them here n there on this internet thing...

my question it will be why do i have to feel so odd abt nobody encourages me to keep doing this kinda things as for edu research

anyway just a small crisis of mine, at the bottom of this

thank You, Florin Florin747 (talk) 19:39, 4 April 2019 (UTC)

If you would like people to devote their time or energy to helping you in some way, you should exhibit some basic politeness by devoting the time and energy necessary to make your question understandable. This includes basic rules of writing (the correct use of capital letters and punctuation, some attempt to spell words correctly), including enough context for readers to know what you're asking about, and questions of venue ("is this the right place for my question?"). --JBL (talk) 16:12, 5 April 2019 (UTC)

Hi, I read Your reply to my post above, I understand that Your are a Mathematician. Thank You, for taking Your time to talk to me. This looks more like a "NO" to me, i mean You dont seem to encourage me keep doing this kinda posts for the future. Let me see what I will be able to do about that. In case Wikipedia dont like my posts , You may do whatever You wish abt it, block my IP, again, for how long would You wish to, no problem with me about that. Thank You for taking Your time to talk to me, I feel awesome about a real Mathematician told me what He considered about my stuff. Yours respectfully, Florin Florin747 (talk) 07:21, 6 April 2019 (UTC)

@Florin747: Just going to point out that a paper claiming a polynomial-time solution to a problem thought to be NP-intermediate will need proper spelling and grammar to be taken seriously. Since Wikipedia's job isn't to conduct original research, all we could help you with is to help you find articles and papers on this subject. Also, you'd have to have a really rigorous proof of a polynomial time bound for whatever algorithm for the problem you propose.--Jasper Deng (talk) 07:32, 6 April 2019 (UTC)

Hi, Mr. Deng! Thank You for clarifying those things to me. To be quite honest, i was thinking that they woulded dig for golden mines in Mathematics much more deep, virtualy in any corner of the world. Maybe i was mistaken and maybe is not the case for my little texts without any proper grammar. Again, to be honest about this one too, i would say that super iq matters in Mathematics, seems to be the elites terithory, no such room for novices, what a hech, thats why those computers are filled with all sort of devices, no offense about that , I am sorry for bringing it up.

Thank You for taking Your time to talk to me, Yours respectfully, Florin Florin747 (talk) 09:51, 6 April 2019 (UTC)

Just to correct a common mistake here, mathematics is not just for people with genius IQ's and PhD's. Amateurs can and occasionally do make contributions; see for example Marjorie Rice. The problem is that there are many more people who think have found something new (i.e. cranks) than actually have, and it's usually a tedious waste of time to review amateur work to see if it contains anything valid. So it's true that people will be unwilling to review your work when it isn't clear and concise, and having correct grammar, spelling and punctuation is a big part of that. If English isn't you first language then it might be a good idea to write up your ideas in your native language and submit them to someone who speaks that language. Also, we're not saying that there is nowhere you can send your ideas, just that we don't accept them at Wikipedia. Wikipedia is a great place to practice your writing and editing skills, and if English is not your native language then you might want to start with your own; there are Wikipedias in over 300 languages and most of them are more in need of work than the one in English. But Wikipedia is also very good a teaching humility; your job here is to pass on the ideas of others, not to submit your own, and even then your carefully crafted work may be removed or changed at any time. --RDBury (talk) 13:26, 6 April 2019 (UTC)

Hi, some of my txt files are written in my Romanian language, not the perfect one either, i send them by e-mail alrite, didnt get too much of any replies. It looks to me that I wont get any success this place either. Thats alrite I will always have something to think about, like Intel 8080 microprocessor and the video games programming , for this one computing machine. It also helps for (re)-finding small ideas like cache-pointer, some way to get faster access to array data, fast updating a pointer using recurence , I meant. This could be also useful to optimize updating data for 3D object rotation, from some point of view related to AI , making the difference between understanding and getting it, in recognition of moving images elements/objects. One after other, I think it's kinda fun. Thank You for taking Your time for me, Florin --Florin747 (talk) 13:48, 6 April 2019 (UTC)

After all this I still have no idea what question was being asked. Is it worth knowing? --JBL (talk) 15:34, 6 April 2019 (UTC)

hi, I agree this aint getting nowhere, thank You for Your time, no need to reply to ths one. Au revoir! :-) Florin747 (talk) 16:04, 6 April 2019 (UTC)