208
addition rule (lemmy.world)
submitted 2 years ago by [email protected] to c/[email protected]
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[-] [email protected] 83 points 2 years ago

Mathematicians write the most insane shit you've ever seen in your life then they're just like □ peace out

[-] [email protected] 12 points 2 years ago

If you wrote the equivalent of this in software I think linus torvalds himself would personally show up to destroy your pc.

[-] [email protected] 4 points 2 years ago

Nah, formulas like that are basically the assembly code for logic.

[-] [email protected] 42 points 2 years ago

statements dreamed up by the utterly deranged

[-] [email protected] 28 points 2 years ago

OP, I need the definition for × and <,> too

[-] [email protected] 28 points 2 years ago

× is the cartesian product and = {x, {x,y}} is the ordered pair of x and y. (i.e., if x is in X and y is in Y, then is the corresponding element of the cartesian product X × Y). hope this helps

[-] [email protected] 12 points 2 years ago

What does type() mean here?

[-] [email protected] 25 points 2 years ago

it's the "order type" of a well ordering on a set. so, given a set X with a total ordering R, type(X,R) is the unique ordinal isomorphic to (X,R)

[-] [email protected] 11 points 2 years ago

what's with the square at the end? isn't that usually for proofs?

[-] [email protected] 15 points 2 years ago

yeah but sometimes when the textbook authors are feeling particularly mischievous they'll just put them in random places. and sometimes they'll even skip the proofs but keep the square.

[-] [email protected] 8 points 2 years ago

Give it up for op actually out here answering questions like a real live teacher.

[-] [email protected] 2 points 2 years ago

Oh wow, I should know that... Thanks

[-] [email protected] 5 points 2 years ago

× is the cartesian product I think, no clue what the other thing is tho

[-] [email protected] 16 points 2 years ago
[-] [email protected] 15 points 2 years ago

This is giving me PTSD flashbacks from Number Theory at uni. What a fascinating mindfuck.

[-] [email protected] 8 points 2 years ago

oh god number theory.... the things they make you do in that class.......

[-] [email protected] 10 points 2 years ago
[-] [email protected] 3 points 2 years ago

Im sorry, but the capital form alone justifies its existence.

[-] [email protected] 5 points 2 years ago

Is this from Principia Mathematica or smth?

[-] [email protected] 7 points 2 years ago

This looks like classical ordinal set theory in relatively modern notation. I’d guess that Principia Mathematica uses batshit notation compared to this but I haven’t read it.

this post was submitted on 01 Feb 2024
208 points (100.0% liked)

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