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
  a<=b-c implies a<=b & c <=b
proof
  assume a<=b-c;
  then a+c <=b by XREAL_1:19;
  hence thesis by Lm7;
end;
