Input:fF[1,22,...,n]of degree d Output:f≡0？ fix an arbitrary S F pick random ri,r2,...,mnES uniformly and independently at random; check whether f(ri,r2,...rn)=0; f=0f(r1,r2,.,rn)=0Input: of degree d Output: f ￾ 0? f 2 F[x1, x2,...,xn] pick random r1, r2, ... , rn ∈S uniformly and independently at random; check whether f(r1, r2, ... , rn) = 0 ; fix an arbitrary S ✓ F f ⌘ 0 f(r1, r2,...,rn)=0