# RDEaux F¶

multi_SPDE(a, b, lc, d, der)
SPDE1(b, c, D) solves Q' + b Q = c and returns [Q, r] where r = c - ( Q' + b Q). That is when r is zero then Q is true solution, otherwise r represets unsolved part of c. Moreover def(r) < deg(bQ). Note: SPDE1 assumes that deg(Q') < deg(bQ) for all Q.