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| -rw-r--r-- | theories/FSets/FSetProperties.v | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/theories/FSets/FSetProperties.v b/theories/FSets/FSetProperties.v index 4aeda775c7..4d8a78a14b 100644 --- a/theories/FSets/FSetProperties.v +++ b/theories/FSets/FSetProperties.v @@ -154,6 +154,11 @@ Module Properties (M: S). Proof. unfold Subset; intuition. Qed. + + Lemma double_inclusion : s1[=]s2 <-> s1[<=]s2 /\ s2[<=]s1. + Proof. + unfold Subset, Equal; split; intros; intuition; generalize (H a); intuition. + Qed. (** properties of [empty] *) |