http://benji3up2kxewkqfcq7buxk2xd6zwy3zggnurkrm3l4cvwy2iipvyyad.onion/mirrors/gmpdoc/Toom-3_002dWay-Multiplication.html
With this x=X(b) and y=Y(b) . Let a polynomial W(t)=X(t)*Y(t) and suppose its coefficients
are W(t) = w4*t^4 + w3*t^3 + w2*t^2 + w1*t + w0 The w[i] are going to be determined, and when they are they’ll give
the final result using w=W(b) , since x*y=X(b)*Y(b)=W(b) .