Set Theory, Logic, and Proofs Flashcards
Weeks 1, 2 and 3 from Seq/series
1
Q
Given sets A and B, how do you show A=B?
A
A ⊂ B and B ⊂ A
2
Q
What does A⊂B mean?
A
x∈A ⇒ x∈B
3
Q
What is the converse of P⇒Q?
A
Q⇒P
4
Q
What is the contrapositive of P⇒Q?
A
¬Q⇒¬P
5
Q
Define “injective.”
A
f(x)=f(y) ⇒ x=y
6
Q
Define “surjective.”
A
∀y∈B ∃x∈A : f(x)=y
