Zulip Chat Archive

Stream: Is there code for X?

Topic: Typeclass for ordered topological space unbounded above


Michael Rothgang (Jan 20 2024 at 21:23):

I'm looking for a typeclass on ordered topological spaces X with the following property:

  • for every a : Xthere is an element b : X such that a < b

The real numbers satisfy this, but that seems like a big special case. Does mathlib have a typeclass for this?

Eric Rodriguez (Jan 20 2024 at 21:27):

docs#NoMaxOrder

Eric Rodriguez (Jan 20 2024 at 21:27):

there's no need for the space to be topological, although I'm sure there's lemmas with both assumptions

Michael Rothgang (Jan 20 2024 at 22:00):

Thanks! In my context, I want to talk about continuous functions into such a domain - so I'll need a topology anyway.

Yury G. Kudryashov (Jan 20 2024 at 22:28):

Then you add [TopologicalSpace X] and possibly [OrderTopology X] to the assumptions.

Michael Rothgang (Jan 20 2024 at 22:33):

My context is #9872 (just one lemma, 7 lines lines :-)), which already has these in the context.


Last updated: May 02 2025 at 03:31 UTC