2014-06-30 18:44:47 +00:00
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-- Copyright (c) 2014 Microsoft Corporation. All rights reserved.
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-- Released under Apache 2.0 license as described in the file LICENSE.
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-- Author: Leonardo de Moura
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2014-09-16 18:44:50 +00:00
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import logic.core.decidable logic.core.inhabited
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2014-09-03 23:00:38 +00:00
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open decidable
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inductive unit : Type :=
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star : unit
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2014-09-04 23:36:06 +00:00
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namespace unit
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notation `⋆`:max := star
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2014-09-19 22:04:52 +00:00
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protected theorem equal (a b : unit) : a = b :=
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rec (rec rfl b) a
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2014-09-02 02:44:04 +00:00
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2014-09-05 05:31:52 +00:00
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theorem eq_star (a : unit) : a = star :=
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equal a star
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2014-07-19 19:09:47 +00:00
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2014-09-19 22:04:52 +00:00
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protected theorem is_inhabited [instance] : inhabited unit :=
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inhabited.mk ⋆
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2014-08-20 22:49:44 +00:00
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2014-09-30 16:02:37 +00:00
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protected definition has_decidable_eq [instance] : decidable_eq unit :=
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2014-09-09 23:07:07 +00:00
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take (a b : unit), inl (equal a b)
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2014-08-20 02:32:44 +00:00
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end unit
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