Unlike the other polynomial functions, convolve() has no intrinsic notion of endianness. It's big endian in, big endian out and little endian in, little endian out.

list(convolve([1, -1, -20], [1, -3]))
[1, -4, -17, 60]
list(convolve([-20, -1, 1], [-3, 1]))
[60, -17, -4, 1]