reserve x,y,z for Real,
  a,b,c,d,e,f,g,h for Nat,
  k,l,m,n,m1,n1,m2,n2 for Integer,
  q for Rational;

theorem Th11:
  k,l are_coprime implies k|^a,l|^b are_coprime
proof
  assume k,l are_coprime;
  then k|^a,l are_coprime by Th10;
  hence thesis by Th10;
end;
