r= x^12 - x^10 + x^8 - x^6 + x^4 - x^2 + 1 q= (x^18 + 2*x^16 + x^14 + x^4 - 2*x^2 + 1) / 4 P= x^9 + 2*x^8+x^7+x^2-2*x+1 v= x^2