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36 lines
389 B
Plaintext
36 lines
389 B
Plaintext
import NNG.Metadata
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import NNG.MyNat.Addition
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import NNG.MyNat.Theorems.Proposition
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Game "NNG"
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World "Proposition"
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Level 8
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Title ""
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open MyNat
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Introduction
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"
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"
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Statement
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""
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(P Q : Prop) : (P → Q) → (¬ Q → ¬ P) := by
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rw [not_iff_imp_false]
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rw [not_iff_imp_false]
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intro f
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intro h
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intro p
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apply h
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apply f
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exact p
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NewLemma not_iff_imp_false
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Conclusion
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"
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"
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