13 lines
357 B
Text
13 lines
357 B
Text
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, int.zero_add, int.right_distrib, int.one_mul]
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