The analysis reveals that every $Σ^1_3$ set is Marczewski measurable, highlighting implications for the projective hierarchy.
We show that in the iterated Sacks model over the constructible universe the Mansfield-Solovay Theorem holds for Σ¹₃ sets. In particular, every Σ¹₃ set is Marczewski measurable and the optimal complexity for a Bernstein set is Δ¹₄. Based on a result by Kanovei, we also briefly show how to separate the Mansfield-Solovay Theorem at non-trivial levels of the projective hierarchy.
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Jonathan Schilhan (2025) studied this question.
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