 It is named after Edwin Hewitt and Leonard Jimmie Savage.Let formula_1 be a sequence of independent and identically-distributed random variables taking values in a set formula_2.The Hewitt–Savage zero–one law says that any event whose occurrence or non-occurrence is determined by the values of these random variables and whose occurrence or non-occurrence is unchanged by finite permutations of the indices, has probability either 0 or 1 (a "finite" permutation is one that leaves all but finitely many of the indices fixed).