# Linda Brown Westrick (Penn State)

When:
December 8, 2020 @ 11:00 am – 12:00 pm
2020-12-08T11:00:00-10:00
2020-12-08T12:00:00-10:00

Title: Luzin’s (N) and randomness reflection
by Linda Brown Westrick (Penn State) as part of Computability theory and applications

Abstract
We show that a computable real-valued function f has Luzin’s property (N) if and only if it reflects Pi^1_1-randomness, if and only if it reflects Delta^1_1-randomness relative to Kleene’s O, and if and only if it reflects Kurtz randomness relative to Kleene’s O. Here a function f is said to reflect a randomness notion R if whenever f(x) is R-random, then x is R-random as well. If additionally f is known to have bounded variation, then we show f has Luzin’s (N) if and only if it reflects weak-2-randomness, and if and only if it reflects Kurtz randomness relative to 0′. This links classical real analysis with algorithmic randomness. Joint with Arno Pauly and Liang Yu.