18 lines
640 B
Text
18 lines
640 B
Text
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abbreviation Bool : Type.{1} := Type.{0}
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variable and : Bool → Bool → Bool
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infixl `∧` 25 := and
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variable and_intro : forall (a b : Bool), a → b → a ∧ b
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variables a b c d : Bool
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axiom Ha : a
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axiom Hb : b
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axiom Hc : c
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check
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have a ∧ b, from and_intro a b Ha Hb,
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have [fact] b ∧ a, from and_intro b a Hb Ha,
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have H : a ∧ b, from and_intro a b Ha Hb,
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have H [fact] : a ∧ b, from and_intro a b Ha Hb,
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then have a ∧ b, from and_intro a b Ha Hb,
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then have [fact] b ∧ a, from and_intro b a Hb Ha,
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then have H : a ∧ b, from and_intro a b Ha Hb,
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then have H [fact] : a ∧ b, from and_intro a b Ha Hb,
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Ha
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