Quantum Invariants
  In super-symmetric quantum theory, or in string theory, (including generalizations of these theories to underlying quantum spaces) we study a certain partition function Z(Q,A,g). Here Q denotes a supercharge, A denotes an observable with the property A^2 = I, and g denotes an element of a symmetry group of Q. The supercharge may depend on a parameter lambda, namely Q = Q(lambda). We give an elementary argument to show that Z, as defined, does not actually depend on lambda. 
Arthur Jaffe