(** *** Order and square function *)

(* Specifications: *)
Lemma Rle_0_sqr : forall r, 0 <= Rsqr r.
Lemma Rlt_0_sqr : forall r, r <> 0 -> 0 < Rsqr r.
#[global]
Hint Resolve Rle_0_sqr Rlt_0_sqr: real.
Lemma Rplus_sqr_eq_0 :
forall r1 r2, Rsqr r1 + Rsqr r2 = 0 -> r1 = 0 /\ r2 = 0.