2025/02/26

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2025-02-26 11:00:22 +0100bilegeek(~bilegeek@2600:1008:b06e:701b:8c92:bcff:3789:c22c) (Quit: Leaving)
2025-02-26 10:59:08 +0100 <tomsmeding> https://ncatlab.org/nlab/show/concept+with+an+attitude
2025-02-26 10:59:04 +0100 <Leary> I'm still not sure what the original statement is supposed to be. f and g are partial functions with opposite co/domains and the property that each is total on the other's range?
2025-02-26 10:58:01 +0100 <[exa]> anyway yeah, I'd say the original definiton would need a bit more of a spirit to it to actually spawn a useful name
2025-02-26 10:57:26 +0100 <[exa]> ah well okay in math that could cause issues, I see
2025-02-26 10:57:24 +0100 <tomsmeding> but if you already have the types of f and g, there's nothing more to specify!
2025-02-26 10:57:10 +0100 <[exa]> f.f doesn't type
2025-02-26 10:56:17 +0100 <tomsmeding> if it's just "f . g", then it's weaker; if you also include "f . f", then it's stronger
2025-02-26 10:55:59 +0100 <tomsmeding> depends on what compositions you mean when you say "compositions of f and g"
2025-02-26 10:55:55 +0100 <[exa]> so I'd say it's the same
2025-02-26 10:55:40 +0100 <[exa]> the totality of the composition implies exactly the domain-is-a-superset property that was requested, and I just run it in both directions
2025-02-26 10:54:41 +0100 <tomsmeding> that's not quite the same statement, is it?
2025-02-26 10:54:37 +0100 <cheater> i don't like puzzle definitions
2025-02-26 10:54:20 +0100 <[exa]> cheater: you can just say that compositions of f and g are total
2025-02-26 10:52:11 +0100 <cheater> that sounds like something out of control theory.
2025-02-26 10:51:20 +0100merijn(~merijn@77.242.116.146) merijn
2025-02-26 10:51:04 +0100xff0x(~xff0x@fsb6a9491c.tkyc517.ap.nuro.jp) (Ping timeout: 272 seconds)
2025-02-26 10:49:13 +0100 <tomsmeding> you can call it a "back-and-forth"
2025-02-26 10:48:39 +0100 <cheater> if no such thing is described then i shall coin that as a speculative function pair (or tuple for a more complex graph)
2025-02-26 10:47:02 +0100tromp(~textual@2a02:a210:cba:8500:b949:287e:6bbd:873b)
2025-02-26 10:46:18 +0100 <cheater> no, they have no such property as stated
2025-02-26 10:45:55 +0100 <cheater> i think that's interesting enough.
2025-02-26 10:45:51 +0100 <tomsmeding> if f and g are continuous and bijective, then they are homeomorphisms, for example
2025-02-26 10:45:48 +0100zmt01(~zmt00@user/zmt00) (Ping timeout: 252 seconds)
2025-02-26 10:45:44 +0100 <cheater> the only property is that if you start in one set, you can infinitely go between the two sets using f and g. possibly ending at some limit element or not.
2025-02-26 10:45:02 +0100 <tomsmeding> cheater: if the functions have some equation relating them, then there may be appropriate terminology, but without any equation relating them, I don't think there's a word for this
2025-02-26 10:44:34 +0100 <cheater> f and g are connected by the property i listed above: they are total on sets that contain each other's codomains
2025-02-26 10:44:02 +0100 <tomsmeding> Leary: That's fair
2025-02-26 10:43:42 +0100 <tomsmeding> (and that's usually modelled as a total function to Y + 1)
2025-02-26 10:43:42 +0100 <cheater> they are total on their domains, but their domains don't have to line up like they do in my hypothesis
2025-02-26 10:43:38 +0100kaskal(~kaskal@84-115-238-111.cable.dynamic.surfer.at) kaskal
2025-02-26 10:43:31 +0100 <tomsmeding> it's the concept of a "partial function" that needs explicit note
2025-02-26 10:43:10 +0100 <tomsmeding> functions are total by default in mathematics
2025-02-26 10:43:04 +0100 <tomsmeding> those are just a pair of functions
2025-02-26 10:42:56 +0100 <tomsmeding> I don't see any connection between f and g here
2025-02-26 10:42:55 +0100 <cheater> a pair of total functions between two sets going in opposite directions
2025-02-26 10:42:40 +0100swamp_(~zmt00@user/zmt00) zmt00
2025-02-26 10:42:37 +0100 <cheater> yes
2025-02-26 10:42:32 +0100 <tomsmeding> cheater: so then that first formula says that f is total? I.e. it returns a result for every x?
2025-02-26 10:42:07 +0100 <Leary> Multiple terminologies can coexist. I also don't consider the language around /releases/ to conflict with the language for the version components.
2025-02-26 10:41:56 +0100 <cheater> tomsmeding: yes. that's a shorthand.
2025-02-26 10:41:16 +0100 <tomsmeding> though actually the GHC wiki terminology is rather close to this
2025-02-26 10:40:32 +0100merijn(~merijn@77.242.116.146) (Ping timeout: 244 seconds)
2025-02-26 10:40:25 +0100 <tomsmeding> Leary: Well, then the GHC user guide disagrees, and the GHC wiki contests the nuance. :P
2025-02-26 10:39:43 +0100 <Leary> tomsmeding: In line with HLS: 9.12 ~ major (version (numbers)); 1 ~ minor (version (number)). At least that's the language I would use; I doubt there's an official decree.
2025-02-26 10:37:22 +0100 <tomsmeding> or something
2025-02-26 10:37:13 +0100 <tomsmeding> perhaps you meant "\A x \in X \E y (f(x) = y)"?
2025-02-26 10:36:59 +0100lxsameer(~lxsameer@Serene/lxsameer) lxsameer
2025-02-26 10:36:04 +0100 <tomsmeding> what do you mean with "\E f(x)"?
2025-02-26 10:35:35 +0100 <cheater> what do you call a pair of functions in mathematics f, g, f: X -> Y and g: Y -> X such that \A x \in X \E f(x) and \A y \in Y \E g(y)?