Definition Qmult_resp_Qlt_pos_l:= Qlt_Qmult_cancel_l: forall t x y : Q, Zero < t -> t * x < t * y -> x < y.

Lemma Qopp_Qone_Qlt_Qone: Qopp Qone < Qone.
Hint Resolve Qinv_pos Qinv_resp_nonzero Qminus_Qeq Qeq_Qminus
Qlt_not_eq' Qinv_neg Qle_Qopp_pos Qlt_Qopp_pos
Qlt_Qopp_neg Qopp_Qone_Qlt_Qone.