43 lines
704 B
Text
43 lines
704 B
Text
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import data.nat
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open nat
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definition f (a b : nat) := a + b
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example (a b : nat) : f a b = 0 → f b a = 0 :=
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begin
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intro h,
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unfold f at h,
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state,
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unfold f,
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state,
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rewrite [add.comm],
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exact h
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end
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example (a b : nat) : f a b = 0 → f b a = 0 :=
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begin
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intro h,
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unfold f at *,
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state,
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rewrite [add.comm],
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exact h
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end
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example (a b c : nat) : f c c = 0 → f a b = 0 → f b a = f c c :=
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begin
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intros [h₁, h₂],
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unfold f at (h₁, h₂),
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state,
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unfold f,
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rewrite [add.comm, h₁, h₂],
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end
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example (a b c : nat) : f c c = 0 → f a b = 0 → f b a = f c c :=
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begin
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intros [h₁, h₂],
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unfold f at * ⊢,
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state,
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unfold f,
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rewrite [add.comm, h₁, h₂],
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end
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