Definition point_in_holed_interval (a b h : R) : R :=
  if Req_dec_T h (Rdiv (Rplus a b) (INR 2)) then (Rdiv (Rplus a h) (INR 2))
  else (Rdiv (Rplus a b) (INR 2)).

Lemma middle_in_interval : forall a b : R, Rlt a b -> (a < (a + b) / INR 2 < b)%R.