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

theorem
  a < 0 & b <= a implies 1 <= b/a
proof
  assume
A1: a < 0;
  assume b <= a;
  then b/a >= a/a by A1,Lm30;
  hence thesis by A1,XCMPLX_1:60;
end;
