theorem
  not 3 divides b|^3 + b|^2 - b + 1
  proof
    A0: (b|^2 + 1) + (b|^3 - b) = b|^3 + b|^2 - b + 1;
    not 3 divides b|^2 + 1 by Th92;
    hence thesis by A0,PEPIN:41,Th58,INT_2:1;
  end;
