NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/sci/math/15161

Internet Message Format | 1992-11-18 | 1.1 KB

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From: [e-mail] (Frank Piessens)
Subject: Question about Finite Limit Sketches and Theories
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Date: Wed, 18 Nov 1992 11:52:11 GMT
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Let S be a finite limit sketch, and let T be its theory.
On page 236 of their book "Category theory for computing science",
Barr and Wells state that it would be incorrect to assume in general
(although it is true in familiar examples) that every node of T
is a limit of a diagram in the graph of S.

Could somebody please point out an example of this? (So give an example
of a sketch, that has a theory in which some node A is not the limit
of a diagram in the graph of the sketch)

Since this is probably not of general interest, please respond by email
to [e-mail]

Thanks in advance,

Frank Piessens.