9 lines
262 B
Text
9 lines
262 B
Text
import data.int
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open int
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constant f : int → int
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definition double (x : int) := x + x
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theorem tst1 (x y : int) (H1 : double x = 0) (H2 : double y = 0) (H3 : f (double y) = 0) (H4 : y > 0) : f (x + x) = 0 :=
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by rewrite ⟨↑double at H1, H1, H2 at H3, H3⟩
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