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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Ditkin set | 1/1 | https://en.wikipedia.org/wiki/Ditkin_set | reference | science, encyclopedia | 2026-05-05T12:04:47.032885+00:00 | kb-cron |
In mathematics, a Ditkin set, introduced by (Ditkin 1939), is a closed subset of the circle such that a function f vanishing on the set can be approximated by functions φnf with φ vanishing in a neighborhood of the set.
== References == Ditkin, V. (1939), "On the structure of ideals in certain normed rings", Uchenye Zapiski Moskov. Gos. Univ. Matematika, 30: 83–130, MR 0002012