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

theorem
  c <= 0 & 0 < a & a <= b implies c/a <= c/b
proof
  assume
A1: c <= 0;
  assume that
A2: a>0 and
A3: a<=b;
  a">=b" by A2,A3,Lm32;
  then a"*c <= b"*c by A1,Lm28;
  then c/a<=b"*c by XCMPLX_0:def 9;
  hence thesis by XCMPLX_0:def 9;
end;
