9 research outputs found

    Increasing the second uniform indiscernible by strongly ssp forcing

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    We introduce a new and natural stationary set preserving forcing Pc−c(λ,μ)\mathbb P^{c-c}({\lambda},{\mu}) that (under NS{\rm NS} precipitous + existence of H_{\theta}^# for a sufficiently large regular θ{\theta}) increases the second uniform indiscernible u2u_2 beyond some given ordinal λ{\lambda}. The forcing Pc−c\mathbb P^{c-c} shares this property with forcings defined in [9] and [2]. As a main tool we use certain natural open two player games which are of independent interest, viz. the capturing games Gcap(X)G^{cap}(X) and the catching-capturing games Gc−c(X)G^{c-c}(X). In particular, these games are used to isolate a special family of countable elementary submodels M≺HθM \prec H_{\theta} that occur as side conditions in Pc−c\mathbb P^{c-c} and thus allow to control the forcing in a strong way

    Incompatible bounded category forcing axioms

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    We introduce bounded category forcing axioms for well-behaved classes Γ\Gamma. These are strong forms of bounded forcing axioms which completely decide the theory of some initial segment of the universe HλΓ+H_{\lambda_\Gamma^+} modulo forcing in Γ\Gamma, for some cardinal λΓ\lambda_\Gamma naturally associated to Γ\Gamma. These axioms naturally extend projective absoluteness for arbitrary set-forcing--in this situation λΓ=ω\lambda_\Gamma=\omega--to classes Γ\Gamma with λΓ>ω\lambda_\Gamma>\omega. Unlike projective absoluteness, these higher bounded category forcing axioms do not follow from large cardinal axioms, but can be forced under mild large cardinal assumptions on VV. We also show the existence of many classes Γ\Gamma with λΓ=ω1\lambda_\Gamma=\omega_1, and giving rise to pairwise incompatible theories for Hω2H_{\omega_2}.Comment: arXiv admin note: substantial text overlap with arXiv:1805.0873

    Generic Large Cardinals and Absoluteness

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    Set Theory

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    Set theory and the analyst

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    This survey is motivated by specific questions arising in the similarities and contrasts between (Baire) category and (Lebesgue) measure - category-measure duality and non-duality, as it were. The bulk of the text is devoted to a summary, intended for the working analyst, of the extensive background in set theory and logic needed to discuss such matters: to quote from the Preface of Kelley [Kel]: "what every young analyst should know"
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