kanovei at wminf2.math.uni-wuppertal.de
Sun Feb 1 04:45:57 EST 1998
>Date: Sat, 31 Jan 1998 10:59:11 -0800
>From: Vaughan Pratt <pratt at cs.stanford.edu>
>think that if two things are isomorphic, then there's not much point in
>distinguishing between them.
>We need a poll.
*We* do not need a poll to understand the difference
between (1) groups as concrete sets with concrete
operations and (2) isomorphism classes of the former.
Algebraists sometimes call (2) groups while (1)
presentations. Everyone knows that (1), even being
algebraically isomorphic, can bear some extra structure
(say topological) which is the mathematical reason to
them from each other despite the group isomorphism.
It remains to wonder is the whole "system of foundations",
so to speak, of category theories, concentrated on
topics of equal mathematical *depth*.
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