Proofs

#folder

Axiom

Definition

An axiom of a mathematical system is a statement that is assumed to be true. No proof is given. From axioms we derive propositions and theorems.

Without Loss of Generality (WLOG)

Definition

With a "symmetric" statement (e.g and is odd), it is only necessary to prove one case and to write "without loss of generality" (e.g without loss of generality, prove for is odd and is even...)

Even, Odd

Definition

An integer is even if it can be written as for , and is odd for for

Logical Connectives

Table

Symbols listed from highest to lowest precedence:

Symbol Informal meaning
negation
conjunction (and, both)
disjunction (or, one of)
implication
if and only if