Two-State Spin System graph G=(V,E)2 states {0,1) configuration o:V→{0，l} A- := weight:w()=]I A().() (u,v)∈E w(o) Gibbs measure: 4(o)= ZAG partition function: Z4(G)=〉(o) o∈{0,1}VTwo-State Spin System A = ￾ A0,0 A0,1 A1,0 A1,1 ￾ = ￾ ￾ 1 1 ￾ ￾ graph G=(V,E) 2 states {0,1} weight: w(￾) = ￾ (u,v)￾E A￾(u),￾(v) Gibbs measure: µ(￾) = w(￾) ZA(G) ZA(G) = ￾ ￾￾{0,1}V partition function: w(￾) configuration ￾ : V ￾ {0, 1}