feat: lemmas about List.filterM - #7423
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These are more general cases of the existing lemmas about `Id`.
eric-wieser
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List.filterM
eric-wieser
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Dec 3, 2025
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| theorem filterM_cons {m : Type → Type v} [Monad m] [LawfulMonad m] {a : α} {as : List α} {p : α → m Bool} : | ||
| filterM p (a :: as) = | ||
| (do let pa ← p a; let as ← filterM p as; return if pa then a :: as else as) := by |
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Or would this be better with applicatives?
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| (do let pa ← p a; let as ← filterM p as; return if pa then a :: as else as) := by | |
| (fun pa as => if pa then a :: as else as) <$> p a <*> filterM p as := by |
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This PR adds proofs about
List.filterM.A few theorems moved to earlier files to make this possible.