19 lines
620 B
Text
19 lines
620 B
Text
prelude
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definition Prop : Type.{1} := Type.{0}
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constant and : Prop → Prop → Prop
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infixl `∧`:25 := and
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constant and_intro : forall (a b : Prop), a → b → a ∧ b
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constants a b c d : Prop
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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 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 : 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 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 : a ∧ b, from and_intro a b Ha Hb,
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Ha
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