Spyke
sik0fewlreply
lemmy.ca

Wouldn't they just look up the answer in a table?

13

Nah not anymore, now you spend a day or so building some convoluted excel calculator once so that you never need to do the calcs again.

Then, 3 years later when you go to add or change something in that calculator, you have absolutely no idea how it works and decide the change wasn't that important anyway.

9
Wilzaxreply
lemmy.world

Hmm yes.. set theory... I don't understand anything happening here

15
MBMreply
lemmings.world

+ is a map from N×N to N where a + 0 = a and a + S(b) = S(a + b) (S is the successor function that gives the next number).
Then 1 + 1 = 1 + S(0) = S(1 + 0) = S(1) = 2.

8

No, it's correct. You define the operation by it's properties. It's not saying that "a plus 0 = a" but "the result of applying the binary operation '+' to any number with 0 should give the original number."

  • is just a symbol. You could instead write it as +(a,0)=a and +(a,S(b))=S(+(a,b)).

You have to have previously defined 1=S(0), 2=S(1), 3=S(2), and so on.

9

Yeah, define "zero".

The one invented on India at around the Middle Age is a different one. The one you are asking about is very old.

6

Not only that, it is mathematically correct, at least given the usual definitions of 1, 2, +, and !

4

I appreciate the latex-style quotes around the mathematician's 1

1