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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeJul 28th 2013
• (edited Jul 28th 2013)

added a brief remark to discrete object in a new section Examples — in infintiy-toposes on the relation between discreteness and cohomology.

This is a (fairly trivial) comment on Mike’s discussion over on the HoTT blog, linked to from the above.

• CommentRowNumber2.
• CommentAuthorTodd_Trimble
• CommentTimeJul 28th 2013

In discrete object I spotted this statement

In Abstract Stone Duality, a space is called discrete if $X \times X \to X$ is open

which didn’t make a whole lot of sense to me; I figure what was really meant is that the diagonal $\delta: X \to X \times X$ is open, so I put that in instead. (Actually, it seems to me one wants to say that both $\delta$ and $\epsilon: X \to 1$ are open, but I don’t have ASD in front of me and I’m not sure what Taylor does.)