lean2/library/data/countable.lean
2015-05-23 20:52:23 +10:00

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/-
Copyright (c) 2015 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
Define countable types
-/
import algebra.function
open function
definition countable (A : Type) : Prop := ∃ f : A → nat, injective f