A notion introduced by Florentin Smarandache: An element x(T, I, F) belongs more than sure to the set M; here T, I, F are real subsets representing the truth, indeterminacy, and falsity percentages respectively, and sup(T)>100.

tautological set are used for universally true propositions where no parameter such as time, space, or subjectivity influences the truth value.

[florentin smarandache, "a unifying field in logics. / neutrosophy: neutrosophic probability, set, and logic", american research press, rehoboth, 1999]