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

theorem
  0 < a & b < a implies b/a < 1
proof
  assume that
A1: a > 0 and
A2: b < a;
  assume b/a >= 1;
  then b/a*a >= 1*a by A1,Lm12;
  hence thesis by A1,A2,XCMPLX_1:87;
end;
