Definition:
A compound proposition that is always true, no matter what the truth values of the propositions that occur in it, is called a tautology(重言式或永真式).
離散數學裏的吧?
contradictory矛盾式
contradiction（or contradictory矛盾式）
satisfiable（可滿足式）
希望妳發現有幫助 ^_^