Definition CReal_inv_pos (x : CReal) (Hxpos : 0 < x) : CReal :=
{|
  seq := CReal_inv_pos_seq x Hxpos;
  scale := CReal_inv_pos_scale x Hxpos;
  cauchy := CReal_inv_pos_cauchy x Hxpos;
  bound := CReal_inv_pos_bound x Hxpos
|}.Definition CReal_neg_lt_pos : forall x : CReal, x < 0 -> 0 < -x.Definition CReal_inv (x : CReal) (xnz : x # 0) : CReal
  := match xnz with
     | inl xNeg => - CReal_inv_pos (-x) (CReal_neg_lt_pos x xNeg)
     | inr xPos => CReal_inv_pos x xPos
     end.Notation "/ x" := (CReal_inv x) (at level 35, right associativity) : CReal_scope.

Lemma CReal_mult_lt_reg_l : forall r r1 r2, 0 < r -> r * r1 < r * r2 -> r1 < r2.