reserve i,j,k,n,m,l,s,t for Nat;
reserve a,b for Real;
reserve F for real-valued FinSequence;
reserve z for Complex;
reserve x,y for Complex;
reserve r,s,t for natural Number;

theorem Th54:
  m gcd (m lcm n) = m
proof
  set M = m lcm n;
  m divides M by NAT_D:def 4;
  hence thesis by Th49;
end;
