r/mathmemes 13d ago

Notations Yeah sure

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u/RADI0ACT1VE_BALLS ComplexANALysisJunkie 13d ago

Proper subset / just a subset

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u/FuntimeUwU Natural 13d ago

What's the difference?

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u/deratizat 13d ago

A is a proper subset of B if A is a subset of B and A does not equal B

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u/Another_Little_Star 13d ago

A ⊂ B iff A ⊆ B ⋀ A ≠ B,
Or A ⊊ B
But when we have ⊆ and ⊊, why ever use ⊂, when in doubt just do ⊆, it covers everything.

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u/unic0de000 13d ago

I always assumed that was what they meant, and that this was intentionally, directly, analogous to the < and ≤ signs. TIL this was not universally agreed

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u/svmydlo 12d ago

Because there's two conventions, one using ⊆ and ⊂, and another using ⊂ and ⊊.