Gives an generalized outer product of two multipols
polyprod(m1, m2, overlap = 0)multipols to be combined
Integer indicating how many variables are common to
m1 and m2; default of zero corresponds to no variables
in common
# NOT RUN {
a <- as.multipol(matrix(1,2,2)) # 1+x+y+xy
polyprod(a,a) # (1+x+y+xy)*(1+z+t+zt) --- offset=0
polyprod(a,a,1) # (1+x+y+xy)*(1+y+z+yz)
polyprod(a,a,2) # (1+x+y+xy)^2
# }