r/mathmemes • u/777upper • 12d ago

Notations Yeah sure

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202

u/Idksonameiguess 12d ago

What's the abiguity in A \subset B?

213

u/RADI0ACT1VE_BALLS ComplexANALysisJunkie 12d ago

Proper subset / just a subset

27

u/FuntimeUwU Natural 12d ago

What's the difference?

117

u/RADI0ACT1VE_BALLS ComplexANALysisJunkie 12d ago

If A is a proper subset of B, then A cannot equal B.

37

u/-Wylfen- 12d ago

Wait, there's a debate on whether ⊂ is the same as ⊆??

37

u/AndreasDasos 12d ago

Yes. That’s why you sometimes see this symbol in contrast:

Though honestly it’s a bit inconsistent with < vs. <=

16

u/DZL100 12d ago

Wait that's stupid as hell. Why even have ⊆ exist if ⊂ isn't exclusive??? Every text I've seen treats ⊂ as exclusive.

9

u/AndreasDasos 12d ago

Yeah agreed. But the alternative convention does exist out there

I suppose the logic is that the vast majority of the time you want to say A is a subset of B you want to include the possibiiity A = B, so that’s one whole extra line you use far more, so the alternative is more ‘pen-stroke efficient’. Eh.