Talk:Coleman–Mandula theorem
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Why has this theorem suddenly been re-christened?
editWhy has the well-known Coleman-Mandula theorem (note hyphen typical of compound adjectives) been suddenly re-christened the "Coleman [en dash] Mandula" theorem? The en-dash is typically used to show intervals but appears in compound words only when one of them already has a hyphen in it. This change seems to me confusing and unnecessary. betsythedevine (talk) 00:59, 29 December 2008 (UTC)
- MoS policy stipulates that the en dash is used whenever there are two different names, such as Coleman and Mandula, while the usual dash - is used if it is a single person, such as Levi-Civita. OpenScience709 (talk) 19:34, 10 January 2023 (UTC)
Direct product of Lie groups is not a Lie algebra
editIn the article the phrasing a symmetry Lie algebra which is always a direct product of the Poincaré group and an internal group is quite wrong. Each direct product of groups is again a group. I suspect that it was intended to say "the direct product of the Lie algebras of the Poincaré group and of an internal group". (Note that the definition of the direct product of two Lie algebras is not too obvious - if one likes to get the Lie algebra of the product group.)
In that way, this internal group must be supposed to be a Lie group, at least to be something like a continuous group. That is, discrete internal symmetries like parity are not concerned. — Preceding unsigned comment added by Stefan Neumeier (talk • contribs) 16:04, 15 January 2014 (UTC)
- The internal Lie algebra is a direct sum of semisimple compact algebras and U(1) algebras. I think these algebras are also called compact and reductive. Ref. Weinberg III. YohanN7 (talk) 13:56, 9 September 2016 (UTC)
Incomprehensible
editI have a modest background in particle physics, but even to me the article is dense. I doubt a layman could comprehend a single sentence. This article will have to be completely rewritten; I just wish I knew enough about this to do so. — Preceding unsigned comment added by 82.139.81.0 (talk) 16:20, 5 March 2014 (UTC)