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| -rw-r--r-- | src/Util/Decidable.v | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/Util/Decidable.v b/src/Util/Decidable.v index 974510f61..482f2c50a 100644 --- a/src/Util/Decidable.v +++ b/src/Util/Decidable.v @@ -126,6 +126,12 @@ Global Instance dec_match_pair {A B} {P : A -> B -> Prop} {x : A * B} : Decidable (let '(a, b) := x in P a b) | 1. Proof. edestruct (_ : _ * _); assumption. Defined. +Global Instance dec_if_bool {b : bool} {A B} {HA : Decidable A} {HB : Decidable B} + : Decidable (if b then A else B) | 10 + := if b return Decidable (if b then A else B) + then HA + else HB. + Lemma not_not P {d:Decidable P} : not (not P) <-> P. Proof. destruct (dec P); intuition. Qed. |