Post #3650699
2026-06-29 13:11 UTC
While teaching a course on algebraic theories last semester I mentioned at some point that the familiar bicomplete categories Top and Poset were not algebraic, but were topological. A student asked about this later on and I found that the #Wikipedia page on «topological category» pointed to categories enriched in Top, not categories with a forgetful functor to Set which is topological. While I have lost a lot of faith in Wikipedia recently, I am pleased to report that https://en.wikipedia.org/wiki/Topological_category is now a disambiguation page.
#math #mathematics #topology #algebra #CategoryTheory
Replies (2)
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@highergeometer@mathstodon.xyz 2026-06-29 14:05
@caten@mathstodon.xyz And there's the third meaning: a category internal to Top....
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@SmartmanApps@dotnet.social 2026-06-30 07:06
@caten@mathstodon.xyz "I have lost a lot of faith in Wikipedia recently" - you only have to look at several of their Maths pages to know any faith is misplaced. The edits are mostly done by people who have no idea what they're talking about (see the page about 0.(9)=1), who never reference any Maths textbooks, despite many of them being freely available on the Internet Archive. Meanwhile edits by actual Maths professors (such as Rick Norwood) get backed out by the admins 🙄