9=2 graph G=(V,E) Boolean symmetric f:10,1dC f=[6,f,,fl where fi=x)for∑xi=i counting edge covers: at every vertex vev, f=[0,1,1,1,1] the at-least-one function holant Π0,1,1,1，，1(gEo） o∈{0,1}Ev∈Vf : {0, 1} Boolean symmetric d ! C at every vertex v∈V, fv = [0, 1, 1, 1..., 1] counting edge covers: the at-least-one function q=2 f = [f0, f1 ,..., fd] where fi = f(x) for Σjxj = i graph G=(V,E) fv holant = X ￾2{0,1}E Y v2V [0, 1, 1, 1,..., 1] ￾ ￾ |E(v) ￾