let a, b, c be Real; :: thesis: ( c < 0 & b < 0 & a < b implies c / a < c / b )
assume that
A1: c < 0 and
A2: b < 0 and
A3: a < b ; :: thesis: c / a < c / b
a " > b " by A2, A3, Lm31;
then (a ") * c < (b ") * c by A1, Lm24;
then c / a < (b ") * c by XCMPLX_0:def 9;
hence c / a < c / b by XCMPLX_0:def 9; :: thesis: verum