diff options
author | notin <notin@85f007b7-540e-0410-9357-904b9bb8a0f7> | 2006-10-17 12:53:34 +0000 |
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committer | notin <notin@85f007b7-540e-0410-9357-904b9bb8a0f7> | 2006-10-17 12:53:34 +0000 |
commit | 28dc7a05cc1d3e03ed1435b3db4340db954a59e2 (patch) | |
tree | 63cdf18cd47260eb90550f62f7b22e2e2e208f6c /theories/Logic/ClassicalEpsilon.v | |
parent | 744e7f6a319f4d459a3cc2309f575d43041d75aa (diff) |
Mise en forme des theories
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9245 85f007b7-540e-0410-9357-904b9bb8a0f7
Diffstat (limited to 'theories/Logic/ClassicalEpsilon.v')
-rw-r--r-- | theories/Logic/ClassicalEpsilon.v | 34 |
1 files changed, 17 insertions, 17 deletions
diff --git a/theories/Logic/ClassicalEpsilon.v b/theories/Logic/ClassicalEpsilon.v index 6c8631a9b..102edba5d 100644 --- a/theories/Logic/ClassicalEpsilon.v +++ b/theories/Logic/ClassicalEpsilon.v @@ -8,7 +8,7 @@ (*i $Id$ i*) -(** *** This file provides classical logic and indefinite description +(** This file provides classical logic and indefinite description (Hilbert's epsilon operator) *) (** Classical epsilon's operator (i.e. indefinite description) implies @@ -23,28 +23,28 @@ Set Implicit Arguments. Axiom constructive_indefinite_description : forall (A : Type) (P : A->Prop), - (exists x, P x) -> { x : A | P x }. + (exists x, P x) -> { x : A | P x }. Lemma constructive_definite_description : forall (A : Type) (P : A->Prop), - (exists! x, P x) -> { x : A | P x }. + (exists! x, P x) -> { x : A | P x }. Proof. -intros; apply constructive_indefinite_description; firstorder. + intros; apply constructive_indefinite_description; firstorder. Qed. Theorem excluded_middle_informative : forall P:Prop, {P} + {~ P}. Proof. -apply - (constructive_definite_descr_excluded_middle - constructive_definite_description classic). + apply + (constructive_definite_descr_excluded_middle + constructive_definite_description classic). Qed. Theorem classical_indefinite_description : forall (A : Type) (P : A->Prop), inhabited A -> - { x : A | (exists x, P x) -> P x }. + { x : A | (exists x, P x) -> P x }. Proof. -intros A P i. -destruct (excluded_middle_informative (exists x, P x)) as [Hex|HnonP]. + intros A P i. + destruct (excluded_middle_informative (exists x, P x)) as [Hex|HnonP]. apply constructive_indefinite_description with (P:= fun x => (exists x, P x) -> P x). destruct Hex as (x,Hx). @@ -90,13 +90,13 @@ Opaque epsilon. (** *** Weaker lemmas (compatibility lemmas) *) Theorem choice : - forall (A B : Type) (R : A->B->Prop), - (forall x : A, exists y : B, R x y) -> - (exists f : A->B, forall x : A, R x (f x)). + forall (A B : Type) (R : A->B->Prop), + (forall x : A, exists y : B, R x y) -> + (exists f : A->B, forall x : A, R x (f x)). Proof. -intros A B R H. -exists (fun x => proj1_sig (constructive_indefinite_description _ (H x))). -intro x. -apply (proj2_sig (constructive_indefinite_description _ (H x))). + intros A B R H. + exists (fun x => proj1_sig (constructive_indefinite_description _ (H x))). + intro x. + apply (proj2_sig (constructive_indefinite_description _ (H x))). Qed. |