Hi everyone! Could you help me with this question please?
Prove that if G is a finite connected graph, then every harmonic function on G is constant.
If G is infinite, must every harmonic function be constant?
Note: A function f:V(G)-> R is harmonic if, for every u in V(G)
f(u)= (1/d(u))* S f(w) (w in N(u))
Thank you in advance!!