The WZMethod(f,r,n,k,cert) command certifies identities of the form .

Let  if  and , otherwise. If the method succeeds in certifying the given identity, the output is a list of two elements  representing the WZ-pair  such that . Otherwise, it returns the error message "WZ method fails".

If the method is successful and if the fifth optional argument cert is given, cert is assigned the WZ certificate .

It is assumed that for each integer ,  and .

Wilf, H., and Zeilberger, D. "Rational function certify combinatorial identities." J. Amer. Math. Soc. Vol. 3. (1990): 147-158.