(** This file is part of the Flocq formalization of floating-point arithmetic in Coq: http://flocq.gforge.inria.fr/  Copyright (C) 2010-2013 Sylvie Boldo #<br /># Copyright (C) 2010-2013 Guillaume Melquiond  This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.  This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the COPYING file for more details. *)
(** * Roundings: properties and/or functions *)
Section RND_prop.
Open Scope R_scope.

Theorem Only_DN_or_UP :
forall F : R -> Prop,
forall x fd fu f : R,
Rnd_DN_pt F x fd -> Rnd_UP_pt F x fu ->
F f -> (fd <= f <= fu)%R ->
f = fd \/ f = fu.