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1. • CommentRowNumber1.
   • CommentAuthorbeppe
   • CommentTimeNov 24th 2018
   • PermaLink
   Author: beppe
   Format: TextHi guys, It seems to me that the definition \Omega-groups [[Omega-group]] in the n-lab page is not correct, since in the original definition given by Higgins in P. J. Higgins, "Groups with multiple operators", Proceedings of the London Mathematical Society, 1956 there is no request for the additional operations to distribute over the group operation. The actual definition given in the n-lab is closest to the notion of categories of interest, in the sense of G. Orzech. In fact, both those notions are of interest and perhaps both of them should be dealt with in the n-lab. I was going to edit the page, but I preferred to share this comment before doing it. Best, Beppe.

   Hi guys,
   
   It seems to me that the definition \Omega-groups Omega-group in the n-lab page is not correct, since in the original definition given by Higgins in
   
   P. J. Higgins, "Groups with multiple operators", Proceedings of the London Mathematical Society, 1956
   
   there is no request for the additional operations to distribute over the group operation. The actual definition given in the n-lab is closest to the notion of categories of interest, in the sense of G. Orzech.
   
   In fact, both those notions are of interest and perhaps both of them should be dealt with in the n-lab.
   
   I was going to edit the page, but I preferred to share this comment before doing it.
   
   Best,
   
   Beppe.
2. • CommentRowNumber2.
   • CommentAuthorTim_Porter
   • CommentTimeNov 25th 2018
   • (edited Nov 25th 2018)
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   Author: Tim_Porter
   Format: MarkdownItexHi there, Beppe, The problem is the Wikipedia page which does not mention Phil Higgins at all. I understood that the term Ω-group was introduced in the paper you mention. (The history needs checking up perhaps.) Grace Orzech's definition probably should be put in a new page entitled [[category of interest]]. A Google seearch suggests that `Ω-group' is used in several different ways in the literature and that Higgins definition is just one which means that the page needs amending. I do not have full access to Phil Higgins paper .... I have a hardcopy somewhere but where is another matter!... so can not check what he says about the relation to groups with operators as is used elsewhere. Can you sort this out? I have added in a new page on categories of interest, but this will be a bit of a stub for the moment. Do add stuff in on the relationship of this stuff to semi-abelian categories etc.

   Hi there, Beppe,

   The problem is the Wikipedia page which does not mention Phil Higgins at all. I understood that the term Ω-group was introduced in the paper you mention. (The history needs checking up perhaps.) Grace Orzech’s definition probably should be put in a new page entitled category of interest. A Google seearch suggests that ‘Ω-group’ is used in several different ways in the literature and that Higgins definition is just one which means that the page needs amending. I do not have full access to Phil Higgins paper …. I have a hardcopy somewhere but where is another matter!… so can not check what he says about the relation to groups with operators as is used elsewhere. Can you sort this out? I have added in a new page on categories of interest, but this will be a bit of a stub for the moment. Do add stuff in on the relationship of this stuff to semi-abelian categories etc.

3. • CommentRowNumber3.
   • CommentAuthorDavidRoberts
   • CommentTimeNov 25th 2018
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   Author: DavidRoberts
   Format: MarkdownItexGo ahead and edit!

   Go ahead and edit!

4. • CommentRowNumber4.
   • CommentAuthorbeppe
   • CommentTimeNov 26th 2018
   • PermaLink
   Author: beppe
   Format: TextHi Tim, thank you for fixing the page, I just added a few lines. -best, Beppe.

   Hi Tim, thank you for fixing the page, I just added a few lines.
   
   -best,
   
   Beppe.