Module 1 Flashcards
What is a proposition?
It is a declarative statement that must be EITHER true or false, not both.
What is the negation operator and what does it do?
~, it turns a statement into it’s inverse. Ex: p = Tom is human. ~p = Tom is not human.
What is the conjunction operator and what does it do?
And (^). p^q is true if, and only if, p and q are both true.
What is the disjunction operator and what does it do?
Or, V, pVq is true if, and only if, p or q are true.
What is the implication operator and what does it do?
Arrow, p implies q. If p is true then q must be true. If p is false then q could be either true or false.
What does p but q mean?
p and q, p^q
What does neither p nor q mean?
Not p and not q, ~p^~q
What is XOR derived from?
P or q and not p and q, (pVq) ^ ~(p^q)
What is the definition of a logical equivalence?
When two statements have logically equivalent forms when identical component statement variables are used to replace identical component statements.
What is De Morgan’s law of conjunction?
The negation of the conjunction of two statements is logically equivalent to the disjunction of their negations.
~(p^q) = ~p V ~q
What is De Morgan’s law of disjunction?
The negation of the disjunction of two statements is logically equivalent to the conjunction of their negations.
~(pVq) = ~p ^ ~q
What is a tautology?
A statement form that is always true regardless of the truth values of the individual statements substituted for its statement variables.
What is a contradiction?
A statement form that is always false regardless of the truth values of the individual statements substituted for its statement variables.
What is the commutative law of conjunction?
p^q = q^p
What is the commutative law of disjunction?
pVq = qVp
What is the associative law of conjunction?
(p^q)^r = p^(q^r)
What is the associative law of disjunction?
(pVq)Vr = pV(qVr)