Let En be the shift operator with respect to n, defined by . For the given set (list)

where the  are hypergeometric terms of n, the ExtendedGosper(T,n) command returns a set (list)

of hypergeometric terms  such that

if each of the hypergeometric term  exists. Otherwise, the ExtendedGosper routine returns the error message ``no solution found''.

Error, (in SumTools:-Hypergeometric:-ExtendedGosper) no solution found

Petkovsek, M.; Wilf, H.; and Zeilberger, D. A=B. Wellesley, Massachusetts: A. K. Peters Ltd., 1996.