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| Auteur principal: | |
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| Format: | Preprint |
| Publié: |
2021
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| Sujets: | |
| Accès en ligne: | https://arxiv.org/abs/2105.06403 |
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- Hjorth, assuming ${\sf{AD+ZF+DC}}$, showed that there is no sequence of length $ω_2$ consisting of distinct $Σ^1_2$-sets. We show that the same theory implies that for $n\geq 0$, there is no sequence of length $δ^1_{2n+2}$ consisting of distinct $Σ^1_{2n+2}$ sets. The theorem settles Question 30.21 of Kanamori, which was also conjectured by Kechris.