9=2 graph G=(V,E) Boolean symmetric f:10,1dC f=[6,f,,jf闭 where fi=x)for∑xi=i counting matchings: at every vertex vev, =[1,1,0,0.,0] the at-most-one function holant ∑Π1,1,0，.…，0(oE@） o∈{0,1}Ev∈Vf = [f0, f1 ,..., fd] where fi = f(x) for Σjxj = i f : {0, 1} Boolean symmetric d ! C at every vertex v∈V, fv = [1, 1, 0, 0..., 0] counting matchings: the at-most-one function q=2 holant = X ￾2{0,1}E Y v2V [1, 1, 0,..., 0] ￾ ￾ |E(v) ￾ graph G=(V,E) fv