reserve X for set;
reserve a,b,c,k,m,n for Nat;
reserve i,j for Integer;
reserve r,s for Real;
reserve p,p1,p2,p3 for Prime;

theorem Th65:
  3|^(2*k),1 are_congruent_mod 8
  proof
    3|^2,1 are_congruent_mod 8 by Lm8;
    then 3|^2|^k,1|^k are_congruent_mod 8 by GR_CY_3:34;
    hence 3|^(2*k),1 are_congruent_mod 8 by NEWTON:9;
  end;
