let a, b, c be Real; :: thesis: ( 0 <= c & b < 0 & a <= b implies c / b <= c / a )
assume that
A1: c >= 0 and
A2: b < 0 and
A3: a <= b ; :: thesis: c / b <= c / a
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 c / b <= c / a by XCMPLX_0:def 9; :: thesis: verum