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Results tagged with induction
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user 334
Tag for questions about induction such as mathematical induction, structural induction or well-founded induction (Noetherian).
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Stuck in a proof about sum types and nonempty lists
Here is my attempt at proving the goal:
Proof.
induction l as [[ | [ | ]] | [ | [ | ]] l IH]; auto.
- cbn.
rewrite IH.
destruct (filter l) as [l' | e'] eqn: Hfilter; [ | reflexivity].
cbn. … If it is true, then it appears that it cannot be proved by a simple structural induction.
Would you have a proof? A counterexample? A hint? …
- 175