Talk: When does Almkvist-Zeilberger's algorithms succeed? Speaker: Shaoshi Chen Abstract: We present two criteria for the existence of telescopers for bivariate hyperexponential-hypergeometric functions. One is for the existence of telescopers with respect to the continuous variable, the other for telescopers with respect to the discrete one. Our criteria are based on a standard representations of bivariate hyperexponential-hypergeometric functions, and two additive decompositions. With those criteria, we determine the termination of Almkvist-Zeilberger's algorithms for bivariate hyperexponential-hypergeometric inputs.