Hypothesis (Hnb_steps : (1 < nb_steps)%Z).

Theorem inbetween_step_Lo :
forall x k l,
inbetween (start + Z2R k * step) (start + Z2R (k + 1) * step) x l ->
(0 < k)%Z -> (2 * k + 1 < nb_steps)%Z ->
inbetween start (start + Z2R nb_steps * step) x (loc_Inexact Lt).