The gfun[`rec+rec`](rec1, rec2, u(n)) command returns a termwise sum of two holonomic recurrences, rec1 and rec2.

If  and  are the sequences defined by rec1 and rec2 respectively, the gfun[`rec+rec`] function returns a recurrence for .

The gfun[`rec*rec`](rec1, rec2, u(n)) command returns a termwise product of two holonomic recurrences, rec1 and rec2.

If  and  are the sequences defined by rec1 and rec2 respectively, the gfun[`rec*rec`] function returns a recurrence for .

The gfun[cauchyproduct](rec1, rec2, u(n)) command returns the Cauchy product of the two holonomic recurrences, rec1 and rec2.

If  and  are the sequences defined by rec1 and rec2 respectively, the gfun[cauchyproduct] function returns a recurrence for their Cauchy product or convolution .