Anybody?

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• gerryflap@feddit.nl ⁨17⁩ ⁨hours⁩ ago

  Okay, so:

  1. 🍇 = 1, because 1 + 1 + 1 = 3
  2. Therefore, 🍪 = 2, because 2 - 1 - 1 = 0
  3. 🥪 is the set of all integer numbers Z, as defined
  4. I am not sure about 🍔, but I assume that it’s the set of integers with all even numbers removed, therefore it’s the set of all odd numbers.

  Beyond that starts the nonsense for me. I’m very curious whether that stuff actually checks out. Some of the terms I remember from group theory, but other stuff seems incorrect to my (limited) knowledge.

  • The second definition of 🍕 seems to contain redundant information, as afar as I can see " --> " defines a morphism, so why is the predicate “φ is a morphism” matter?

  • The first definition of 🍕 with the contravariant thing also doesn’t parse for me, what does that “-” mean in the function arguments?

  • In the definition of 🌭, what is the n (or the P)? ChatGPT started yapping about real projective space, but I’m not sure if that’s correct.

  If there’s an actual mathematician here who knows then I’d love to know the answer. I’ve kinda been nerd sniped by this question but I don’t possess the knowledge to fully get this one

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  • kogasa@programming.dev ⁨2⁩ ⁨hours⁩ ago

    🍕(–, B) : C -> Set denotes the contravariant hom functor, normally written Hom(–, B).

    In this case, C is a category, and B is a fixed object in that category. For any given object X in C, the hom-set Hom(X, C) is the set of morphisms X -> B in C. For a morphism f : X -> Y in C, the Set morphism Hom(f, B) : Hom(Y, B) -> Hom(X, B) is defined by sending each g : Y -> B to gf : X -> B. This is the mapping C -> Set defined by Hom(–, C), and it’s a (contravariant) functor because it respects composition: if h : X -> Y and f : Y -> Z then fh : X -> Z and Hom(fh, C) = Hom(h, C)Hom(f, C) sends g : Z -> B to gfh.

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  • MBM@lemmings.world ⁨7⁩ ⁨hours⁩ ago

    🍔 is the set of integers modulo 2 (more literally, if two integers differ by an even integer you consider them the same). I can write out the rest in a bit.

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  • Zenoctate@lemmy.world ⁨10⁩ ⁨hours⁩ ago

    All I can say is that P(ℝ) refers to a power set of ℝ (all rational numbers). Although I don’t know what n stands for in Pⁿ(ℝ)

    Basically P(A), where A = {1,2,3}, equal {Φ,1,2,3,(1,2),(2,3),(1,3),(1,2,3)}

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    • gerryflap@feddit.nl ⁨8⁩ ⁨hours⁩ ago

      Yeah this was a possibility I was thinking as well. The superscript n could just be n recursive applications, but then n is still not defined. It’s one of the things that makes me thing that it’s just nonsense. Also, how do you do math on Lemmy? Can you just use LaTeX math syntax or did you copy those symbols?

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• MissJinx@lemmy.world ⁨21⁩ ⁨hours⁩ ago

  How insane you have to be to do math with letters?! Math uses numbers you dumbs!

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  • Zenoctate@lemmy.world ⁨21⁩ ⁨hours⁩ ago

    Maths also uses my life to solve too

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