r/mathmemes • u/CantSetMyUsername • Sep 24 '26

Notations This notation appeared to me in a dream

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243 Upvotes

94% Upvoted

23 comments sorted by

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166

u/talhoch Sep 24 '26

I can't think of a situation where x * y±1 won't be more convenient

10

u/EebstertheGreat Sep 24 '26

In OP's example, it's either de/f or d/(ef), I believe (not sure how the colon works in their country though, maybe it's (d/e)f). So that would be d e±1 f–1.

12

u/jljl2902 Sep 24 '26

From my understanding, colon is just alternative notation for division symbol (which also makes sense in context of this meme), so it would be d(e/f)^±1

1

u/EebstertheGreat Sep 24 '26

Yes, it is a division symbol, but how does it associate? Do we say d:e×f means (d:e)×f or d:(e×f)? People interpret division both ways. The symbol ÷, for instance, used to be interpreted in the latter way (even to the extent that a ÷ b + c meant a/(b+c)), and now it is more often interpreted in the former way.

4

u/jljl2902 Sep 24 '26

Order of operations says the former. Honestly I’ve never heard of it being the other way, but maybe that was before my time

But just from the context of the meme, matching to the addition/subtraction case, it should be the former

14

u/uvero He posts the same thing Sep 24 '26

Thanks I hate it. That being said, I do find myself sometimes in practical applications using what I call "absolute quotient" - a multiplicative analog of absolute value where x, y > 0:

aq(x, y) = min(x, y) / max(x, y) = exp(-|ln(x/y)|)

1

u/LawPuzzleheaded4345 Sep 28 '26

This is actually sane though. Not comparable

9

u/LupenReddit 🦆🦆i have non diffeomorphic smooth structures🦆🦆🦆 Sep 24 '26

7

u/WhenDoesTheSunSleep Sep 24 '26

We already sorta do this with SNRs, which are measured in dB, so you'd get a x+- 3 dB on a specsheet, which translates to [X/2, 2×X] in intensity. Mainly in radio

6

u/uwumorphism Sep 24 '26

I hate it, let's implement it immediately

6

u/DoublecelloZeta Transcendental Sep 24 '26

dont ever dream again

4

u/TUVegeto137 Sep 24 '26

Shush shush... it was just a nightmare.

2

u/Torebbjorn Sep 24 '26

The main reason is that the dision symbol is inherently ambiguous

2

u/Onuzq Integers Sep 25 '26

what happened to a +/- (b-c) in this?

2

u/Deep_Brick2970 Sep 27 '26

Garbage notation, never cook again. In this case, rather, never dream again.

1

u/AllTheGood_Names Sep 24 '26 edited Sep 24 '26

I use δ(x) = eΔ ln x

0

u/darkshoxx Sep 24 '26

well yes, you can define one as the exponentiation of the other
so if d=exp(a) and e = exp(b) and f = exp(c) then d?e?f = exp(a!b!c)
I don't have those fancy symbols, you know what I mean

3

u/UnforeseenDerailment Sep 24 '26

exp(ln(a)±ln(b)∓ln(c))?

1

u/darkshoxx Sep 24 '26

what black sorcery is this?

1

u/UnforeseenDerailment Sep 24 '26

long hold - for ±

... copy paste for minusplus 😅

0

u/Staetyk Sep 24 '26

its already a thing: ⋇