
/**  XGhgCan, Cancelation Theorem for Ghg **/
/*A: K McIsaac*/
/*S: University of Western Australia, Nedlands 6009, Australia*/
/*D: June 1986 */
/*K: Ghg, Hypergeometric, Cancelation */

/*: Cancel[($e:All)] is a substitution to apply the cancellation property of
    hypergeometric series. Any parameter matching $e and negative integers 
    are not cancelled. */
Cancel[] : Ghg[$p,$q,#[$x,$$a],#[$y_=$y = $x & ~Natp[1-$y],$$b],$z] -> \
				 Ghg[$p-1,$q-1,#[$$a],#[$$b],$z]
Cancel[$e] : Ghg[$p,$q,#[$x_=~P[$x=$e],$$a],\
   #[$y_=$y = $x & ~Natp[1-$y],$$b],$z] -> Ghg[$p-1,$q-1,#[$$a],#[$$b],$z]

