# ReductionOfOrder(F, L)¶

ReduceOrder(op, s) returns op1 such that for any solution z of op1 z = 0, y = s \int z is a solution of op y = 0. s must satisfy op s = 0.
ReduceOrder(op, [f1, ..., fk]) returns [op1, [g1, ..., gk]] such that for any solution z of op1 z = 0, y = gk \int(g_{k-1} \int(... \int(g1 \int z)...) is a solution of op y = 0. Each fi must satisfy op fi = 0.