14 lines
497 B
Text
14 lines
497 B
Text
/- Minimized example extracted from verifying the Collatz conjecture for small numbers.
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Suggested by Bhavik Mehta (@b-mehta). -/
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def collatzStep (n : Nat) : Nat := if n % 2 = 0 then n / 2 else (3 * n + 1) / 2
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def manyStep (n m : Nat) : Nat → Bool
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| 0 => false
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| k + 1 => m < n ∨ manyStep n (collatzStep m) k
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def checkAll (gas : Nat) : Nat → Bool
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| 0 => true
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| n + 1 => bif manyStep (n + 2) (n + 2) gas then checkAll gas n else false
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example : checkAll 70 100 = true := by cbv
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