S1, C2: Logic Flashcards
1
Q
Converse
A
The converse of A => B is B => A.
2
Q
Equivalence
A
P is equivalent to Q if P is true iff Q is true. P Q.
3
Q
Negation
A
The negation of P is ¬P (not P).
4
Q
Contrapositive
A
The contrapositive of P => Q is ¬Q => ¬P. These two statements are equivalent.
5
Q
The statement P => Q is equivalent to
A
¬P ‘or’Q
6
Q
Injective
A
A function f: A -> B is injective if for all s, t ∈ A s.t. s =/ t, then f(s) =/ f(t).
7
Q
Surjective
A
We say that f is surjective if, for each b ∈ B, there
exists at least one element a ∈ A such that f(a) = b.
