I am reading about GKR protocol from Justin Thaler's book - Proofs, Arguments & Zero Knowledge Page 61, Lemma 4.7 $W_i(z) = \sum_{b,c \in \lbrace 0,1 \rbrace^{k_{i+1}}} add_i (z,b,c)\cdot (W_{i+1}(b)+W_{i+1}(c)) + mult_i(z,b,c)\cdot (W_{i+1}(b)\cdot W_{i+1}(c))$ The above is the equation on which...