1.8 Proof Methods and Strategies Flashcards
1
Q
Proof by cases
A
Proving by considering different cases
p1-> q
p2->q
p3->q
——–
p->q
2
Q
Constructive proof of existence
A
Proving ∃
2
Q
Constructive proof of existence
A
Proving ∃x by finding an element a (called the witness) such that P(a) is true
3
Q
Non-constructive proof
A
Not finding an element where P(a) is true
Example: Using proof by contradiction to show that the negation of ∃x implies a contradiction
4
Q
Uniqueness proof
A