Important: The diffalg package has been deprecated. Use the superseding package DifferentialAlgebra instead.

Let fp and fq denote the leaders of p and q. The function delta_leader returns a sequence, if it exists, of derivations s such that fp = differentiate (fq, s, R).

The function returns FAIL if p or q belongs to the ground field of R or if fp and fq are derivatives of different differential indeterminates.

The command with(diffalg,delta_leader) allows the use of the abbreviated form of this command.