def dmp_trunc(f, p, u, K):
 return dmp_strip([dmp_rem(c, p, (u - 1), K) for c in f], u)

def dmp_trunc ( f , p , u , K ) : return dmp_strip ( [ dmp_rem ( c , p , ( u - 1 ) , K ) for c in f ] , u )
reduce a k[x] polynomial modulo a polynomial p in k[y] .