12 Feb
2017
12 Feb
'17
7:46 p.m.
Dear Jean, As you asked for comments, let me mention that, If I understand well your definition of 'transportable', it is exactly what Charles called a 'hypermorphism functor" which he defined in relation to his notion of "esp?ce de structures" around 1957 to 'categorize' the Bourbaki's definition. Thus your proposed definition " p is a structure ... if it is faithful and transportable " exactly corresponds to Charles' definition of a "foncteur d'homomorphismes". (Cf. for instance def. 19, p. 71 of his book "Cat?gories et Structures", Dunod, 1965.) Friendly yours Andree [For admin and other information see: http://www.mta.ca/~cat-dist/ ]