reserve x for set;
reserve i,j for Integer;
reserve n,n1,n2,n3 for Nat;
reserve K,K1,K2,K3 for Field;
reserve SK1,SK2 for Subfield of K;
reserve ek,ek1,ek2 for Element of K;
reserve p for Prime;
reserve a,b,c for Element of GF(p);
reserve F for FinSequence of GF(p);

theorem Th12:
  1 = 1.(GF p)
  proof
    1 < p by INT_2:def 4;
    then 1 in Segm p by NAT_1:44;
    hence thesis by SUBSET_1:def 8;
  end;
