intro; unfold Rsqr_intruder_distance in |- *; apply Rplus_le_le_0_compat;
apply Rle_0_sqr.
Qed.
Definition e (t : R) : R := sqrt (Rsqr_evader_distance t).
Definition i (t : R) : R := sqrt (Rsqr_intruder_distance t).

(* Specifications: *)
Lemma conflict_T_e_0 : conflict T = true -> (e T <= ConflictRange)%R.
Proof with trivial.