/** Order term function (for truncated power series). */
DECLARE_FUNCTION_1P(Order)
+/** Inert differentiation. */
+DECLARE_FUNCTION_2P(Diff)
+
+/** Inert partial differentiation operator. */
+DECLARE_FUNCTION_2P(Derivative)
+
ex lsolve(const ex &eqns, const ex &symbols);
ex ncpower(const ex &basis, unsigned exponent);