14 lines
353 B
Text
14 lines
353 B
Text
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import data.int
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open int
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theorem abs_thm1 (a b : int) : a - b = a + -b :=
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by rewrite ↑sub -- unfold sub
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theorem abs_thm2 (a b : int) : a - b = a + -b :=
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by rewrite ^sub -- unfold sub
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definition double (x : int) := x + x
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theorem double_zero (x : int) : double (0 + x) = (1 + 1)*x :=
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by rewrite ⟨↑double, zero_add, mul.right_distrib, one_mul⟩
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