2015-02-06 20:57:42 +00:00
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import data.nat
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open nat
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2015-07-07 23:37:06 +00:00
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definition f [unfold 2] (x y z : nat) : nat :=
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2015-02-06 20:57:42 +00:00
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x + y + z
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2015-07-07 23:37:06 +00:00
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attribute of_num [unfold 1]
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2015-02-06 20:57:42 +00:00
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example (x y : nat) (H1 : f x 0 0 = 0) : x = 0 :=
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begin
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2015-10-14 19:27:09 +00:00
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rewrite [↑f at H1, 4>nat.add_zero at H1, H1]
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2015-02-06 20:57:42 +00:00
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end
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