reserve i,i1,i2,i3,i4,i5,j,r,a,b,x,y for Integer,
  d,e,k,n for Nat,
  fp,fk for FinSequence of INT,
  f,f1,f2 for FinSequence of REAL,
  p for Prime;
reserve fr for FinSequence of REAL;
reserve fr,f for FinSequence of INT;
reserve b,m for Nat;

theorem Th12:
  i divides j implies i gcd j = |.i.|
proof
  assume i divides j;
  then |.i.| gcd |.j.| = |.i.| by NEWTON:49,INT_2:16;
  hence thesis by INT_2:34;
end;
