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

theorem
  0 <= c & b < 0 & a <= b implies c/b <= c/a
proof
  assume that
A1: c>=0 and
A2: b<0 and
A3: a<=b;
  a">=b" by A2,A3,Lm33;
  then a"*c>=b"*c by A1,Lm12;
  then c/a>=b"*c by XCMPLX_0:def 9;
  hence thesis by XCMPLX_0:def 9;
end;
