Proof of a Conjecture of Wilf and Zeilberger

@inproceedings{Abramov2001ProofOA,
  title={Proof of a Conjecture of Wilf and Zeilberger},
  author={Sergei A. Abramov},
  year={2001}
}
Wilf and Zeilberger conjectured in 1992 that a hypergeometric term is proper-hypergeometric if and only if it is holonomic. We prove a version of this conjecture in the case of two discrete variables.