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
  n gcd m divides n lcm m
proof
A1: n divides n lcm m by NAT_D:def 4;
  n gcd m divides n by NAT_D:def 5;
  hence thesis by A1,NAT_D:4;
end;
