ground_2 released and permanently renamed as ground

[helm.git] / matita / matita / contribs / lambdadelta / ground / lib / bool.ma

diff --git a/matita/matita/contribs/lambdadelta/ground/lib/bool.ma b/matita/matita/contribs/lambdadelta/ground/lib/bool.ma
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+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||M||                                                             *)
+(*      ||A||       A project by Andrea Asperti                           *)
+(*      ||T||                                                             *)
+(*      ||I||       Developers:                                           *)
+(*      ||T||         The HELM team.                                      *)
+(*      ||A||         http://helm.cs.unibo.it                             *)
+(*      \   /                                                             *)
+(*       \ /        This file is distributed under the terms of the       *)
+(*        v         GNU General Public License Version 2                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+include "basics/bool.ma".
+include "ground/lib/relations.ma".
+include "ground/notation/functions/no_0.ma".
+include "ground/notation/functions/yes_0.ma".
+
+(* BOOLEAN PROPERTIES *******************************************************)
+
+interpretation "boolean false" 'no = false.
+
+interpretation "boolean true" 'yes = true.
+
+(* Basic properties *********************************************************)
+
+lemma commutative_orb: commutative … orb.
+* * // qed.
+
+lemma orb_true_dx: ∀b. (b ∨ Ⓣ) = Ⓣ.
+* // qed.
+
+lemma orb_true_sn: ∀b. (Ⓣ ∨ b) = Ⓣ.
+// qed.
+
+lemma commutative_andb: commutative … andb.
+* * // qed.
+
+lemma andb_false_dx: ∀b. (b ∧ Ⓕ) = Ⓕ.
+* // qed.
+
+lemma andb_false_sn: ∀b. (Ⓕ ∧ b) = Ⓕ.
+// qed.
+
+lemma eq_bool_dec: ∀b1,b2:bool. Decidable (b1 = b2).
+* * /2 width=1 by or_introl/
+@or_intror #H destruct
+qed-.
+
+(* Basic inversion lemmas ***************************************************)
+
+lemma orb_inv_false_dx: ∀b1,b2:bool. (b1 ∨ b2) = Ⓕ → b1 = Ⓕ ∧ b2 = Ⓕ.
+* normalize /2 width=1 by conj/ #b2 #H destruct
+qed-.
+
+lemma andb_inv_true_dx: ∀b1,b2:bool. (b1 ∧ b2) = Ⓣ → b1 = Ⓣ ∧ b2 = Ⓣ.
+* normalize /2 width=1 by conj/ #b2 #H destruct
+qed-.