https://slides.com/georgelee/ics141-applications-equivalences/live
http://clientsfromhell.net/
Where you write code twice
(once as a test case, once to get the test to pass)
A system specification that does not contain any contradictions.
SELECT * FROM users
WHERE status = 1
AND (email = 'test@hawaii.edu' OR email = 'admin@hawaii.edu');
A compound proposition that is always true, no matter what the values of the propositional variables are.
i.e. p v ¬p
A compound proposition that is always false, no matter what the values of the propositional variables are.
i.e. p ^ ¬p
A compound proposition that is neither a contradiction nor a tautology (pretty much anything else)
Two expressions that have the same truth values in all cases are logically equivalent.
Or, let p and q be two compound propositions, p and q are logically equivalent if p↔q is a tautology.
Sometimes denoted as ≡