18This does not show for very small temperatures in the simulation with the Metropolis algorithm. As we decrease the temperature β ≫ βc  , it takes many improbable steps to move from a state with ∑
  isi = M1  to a state with ∑
  isi = − M1  . The Monte Carlo simulation consists of a finite number of steps, therefore we may obtain a non zero  ∑
⟨  isi⟩ , an incorrect result.