Def: An "implication" p => q is true if p is false or q is true.
Truth table
p q p => q q => p p <=> q
-------------------------------------------
T T T T T
T F F T F
F T T F F
F F T T T
False implies everything is true
ex: pig flies => I'm a kind True!
Think about the following statement:
"This statement is false"
If the statement is false, then the statement is true (which is a contradiction!)
Def: an "axiom" is a proposition that is assumed to be true.
ex: if a = b and b = c, then a = c
Truth table
p q p => q q => p p <=> q
-------------------------------------------
T T T T T
T F F T F
F T T F F
F F T T T
False implies everything is true
ex: pig flies => I'm a kind True!
Think about the following statement:
"This statement is false"
If the statement is false, then the statement is true (which is a contradiction!)
Def: an "axiom" is a proposition that is assumed to be true.
ex: if a = b and b = c, then a = c