b5122b6a7b
This change * moves `termination_by` and `decreasing_by` next to the function they apply to * simplify the syntax of `termination_by` * apply the `decreasing_by` goal to all goals at once, for better interactive use. See the section in `RELEASES.md` for more details and migration advise. This is a hard breaking change, requiring developers to touch every `termination_by` in their code base. We decided to still do it as a hard-breaking change, because supporting both old and new syntax at the same time would be non-trivial, and not save that much. Moreover, this requires changes to some metaprograms that developers might have written, and supporting both syntaxes at the same time would make _their_ migration harder.
20 lines
400 B
Text
20 lines
400 B
Text
def g (t : Nat) : Nat := match t with
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| (n+1) => match g n with
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| 0 => 0
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| m + 1 => match g (n - m) with
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| 0 => 0
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| m + 1 => g n
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| 0 => 0
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decreasing_by all_goals sorry
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attribute [simp] g
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#check g._eq_1
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#check g._eq_2
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theorem ex3 : g (n + 1) = match g n with
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| 0 => 0
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| m + 1 => match g (n - m) with
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| 0 => 0
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| m + 1 => g n := by
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conv => lhs; unfold g
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