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Add modus-ponens
author atton <atton@cr.ie.u-ryukyu.ac.jp>
date Thu, 09 Feb 2017 06:32:03 +0000
parents fe247f476ecb
children
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open import systemT
open import Relation.Binary.PropositionalEquality

module boolean where

_and_ : Bool -> Bool -> Bool
T and b = b
F and _ = F

_or_ : Bool -> Bool -> Bool
T or _ = T
F or b = b

not : Bool -> Bool
not T = F
not F = T

De-Morgan's-laws : (a b : Bool) -> (not a) and (not b) ≡ not (a or b)
De-Morgan's-laws T T = refl
De-Morgan's-laws T F = refl
De-Morgan's-laws F T = refl
De-Morgan's-laws F F = refl