The gfun[holexprtodiffeq](expr, y(z)) command produces a differential equation satisfied by the holonomic expression expr.

If expr is a holonomic expression, then the gfun[holexprtodiffeq] function returns a differential equation in y and z that is satisfied by expr. Initial conditions are returned when possible.

Not all holonomic functions are recognized by holexprtodiffeq. It currently accepts the following functions.