what is tautology in discrete mathematics

In discrete mathematics, a tautology is a compound statement that is always true for every value of individual statements. The word "tautology" is derived from a Greek word where "tauto" means "same" and "logy" means "logic". Tautologies can be easily translated into mathematical expressions from ordinary language by using logical symbols. A tautology can be represented with the help of truth tables, which show that the statement being tested is always true no matter the values of the other statements. The opposite of a tautology is a contradiction or fallacy, which is always false.