reserve a,b,c,d for Real;
reserve r,s for Real;

theorem
  0 < a & a <= b implies 1 <= b/a
proof
  assume that
A1: 0<a and
A2: a<=b;
  b/a>=a/a by A1,A2,Lm25;
  hence thesis by A1,XCMPLX_1:60;
end;
