22 lines
604 B
Text
22 lines
604 B
Text
/-
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Copyright (c) 2016 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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-/
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prelude
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import init.logic
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theorem unit_eq (a b : unit) : a = b :=
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unit.rec_on a (unit.rec_on b rfl)
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theorem unit_eq_unit (a : unit) : a = () :=
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unit_eq a ()
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definition unit_subsingleton [instance] : subsingleton unit :=
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subsingleton.intro unit_eq
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definition unit_is_inhabited [instance] : inhabited unit :=
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inhabited.mk ()
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definition unit_has_decidable_eq [instance] : decidable_eq unit :=
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take (a b : unit), decidable.tt (unit_eq a b)
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