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(*         *   The Coq Proof Assistant / The Coq Development Team       *)
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(*         *     GNU Lesser General Public License Version 2.1          *)
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Local Open Scope R_scope.

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Lemma nonpos_derivative_1 :
forall (f:R -> R) (pr:derivable f),
(forall x:R, derive_pt f x (pr x) <= 0) -> decreasing f.