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List.foldl と List.foldr の説明が不適当 #923

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Seasawher opened this issue Sep 30, 2024 · 0 comments · Fixed by #924
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List.foldl と List.foldr の説明が不適当 #923

Seasawher opened this issue Sep 30, 2024 · 0 comments · Fixed by #924
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Seasawher commented Sep 30, 2024 •
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問題点として、本文で挙げられている List.sum 関数などは List.foldl の例として紹介されているが、実際には List.foldr の方と definitionally equal になっている。

example : List.foldr (f := (· + ·)) (init := 0) = List.sum := by rfl
@Seasawher Seasawher changed the title List.foldl は末尾再帰だが、例示した List.sum などは末尾再帰ではない List.foldl と List.foldr の説明が不適当 Sep 30, 2024
@Seasawher Seasawher self-assigned this Sep 30, 2024
Seasawher added a commit that referenced this issue Sep 30, 2024
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List.foldl と List.foldr の説明が不適当
7671f25 
Fixes #923
@Seasawher Seasawher mentioned this issue Sep 30, 2024
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List.foldl と List.foldr の説明が不適当 lean-ja/lean-by-example
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