Definition: n-Tuple An n-Tuple (a1,⋯,an) is a set of n ordered pairs {(1,a1),⋯,(n,an)} Theorem: Equality of n-Tuples Two n-tuples (a1,⋯,an) and (b1,⋯,bn) are equal if and only if a1=b1,⋯,an=bn: (a1,⋯,an)=(b1,⋯,bn)⟺a1=b1∧⋯∧an=bn PROOF TODO