Definition e (t : R) : R := sqrt (Rsqr_evader_distance t).Definition i (t : R) : R := sqrt (Rsqr_intruder_distance t).

Lemma rho_t_le : forall t1 t2 : R, (t1 <= t2)%R -> (rho_vi * t1 <= rho_vi * t2)%R.