Increasing the second uniform indiscernible by strongly ssp forcing

We use side condition techniques to introduce a natural stationary set preserving forcing <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper P Superscript bold c bold c Baseline left-parenthesis lamda comma mu right-parenthesis"> <mml:semantics> <mml:mrow> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="double-struck">P</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">c</mml:mi> <mml:mi mathvariant="bold">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msup> <mml:mo stretchy="false">(</mml:mo> <mml:mi> λ </mml:mi> <mml:mo>,</mml:mo> <mml:mi> μ </mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">\mathbb {P}^{\mathbf {cc}}(\lambda ,\mu )</mml:annotation> </mml:semantics> </mml:math> </inline-formula> that (under <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="sans-serif upper N sans-serif upper S Subscript omega 1"> <mml:semantics> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="sans-serif">N</mml:mi> <mml:mi mathvariant="sans-serif">S</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mi> ω </mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:mrow> </mml:msub> <mml:annotation encoding="application/x-tex">\mathsf {NS}_{\omega _1}</mml:annotation> </mml:semantics> </mml:math> </inline-formula> precipitous + existence of <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper H Subscript theta Superscript number-sign"> <mml:semantics> <mml:msubsup> <mml:mi>H</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi> θ </mml:mi> </mml:mrow> <mml:mi mathvariant="normal"> # </mml:mi> </mml:msubsup> <mml:annotation encoding="application/x-tex">H_{\theta }^\#</mml:annotation> </mml:semantics> </mml:math> </inline-formula> for a sufficiently large regular <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="theta"> <mml:semantics> <mml:mi> θ </mml:mi> <mml:annotation encoding="application/x-tex">\theta</mml:annotation> </mml:semantics> </mml:math> </inline-formula> ) increases the second uniform indiscernible <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="bold u 2"> <mml:semantics> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">u</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> <mml:annotation encoding="application/x-tex">\mathbf {u}_2</mml:annotation> </mml:semantics> </mml:math> </inline-formula> beyond some given ordinal <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="lamda"> <mml:semantics> <mml:mi> λ </mml:mi> <mml:annotation encoding="application/x-tex">\lambda</mml:annotation> </mml:semantics> </mml:math> </inline-formula> . The forcing <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper P Superscript bold c bold c"> <mml:semantics> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="double-struck">P</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">c</mml:mi> <mml:mi mathvariant="bold">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msup> <mml:annotation encoding="application/x-tex">\mathbb {P}^{\mathbf {cc}}</mml:annotation> </mml:semantics> </mml:math> </inline-formula> shares this property with forcings defined by Claverie and Schindler [J. Symbolic Logic 74 (2009), pp. 187–200] and Ketchersid, Larson, and Zapletal [J. Symbolic Logic 72 (2007), pp. 1372–1378]. We show that <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper P Superscript bold c bold c"> <mml:semantics> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="double-struck">P</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">c</mml:mi> <mml:mi mathvariant="bold">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msup> <mml:annotation encoding="application/x-tex">\mathbb {P}^{\mathbf {cc}}</mml:annotation> </mml:semantics> </mml:math> </inline-formula> is in addition <italic>strongly</italic> ssp. As a main tool we use certain natural open two player games which are of independent interest, viz. the capturing games <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="bold upper G Subscript upper M Superscript bold c bold p Baseline left-parenthesis upper X right-parenthesis"> <mml:semantics> <mml:mrow> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">G</mml:mi> </mml:mrow> <mml:mi>M</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">c</mml:mi> <mml:mi mathvariant="bold">p</mml:mi> </mml:mrow> </mml:mrow> </mml:msubsup> <mml:mo stretchy="false">(</mml:mo> <mml:mi>X</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">\mathbf {G}^{\mathbf {cp}}_M(X)</mml

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Proceedings of the American Mathematical Society
Published
2026-02-02
DOI
https://doi.org/10.1090/proc/17522
Primary Topic
Advanced Topology and Set Theory
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article
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article

Increasing the second uniform indiscernible by strongly ssp forcing

Boban Veličković, Ben De Bondt
Proceedings of the American Mathematical Society
Advanced Topology and Set Theory
article

Increasing the second uniform indiscernible by strongly ssp forcing

Boban Veličković, Ben De Bondt
article en

Abstract

We use side condition techniques to introduce a natural stationary set preserving forcing <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper P Superscript bold c bold c Baseline left-parenthesis lamda comma mu right-parenthesis"> <mml:semantics> <mml:mrow> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="double-struck">P</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">c</mml:mi> <mml:mi mathvariant="bold">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msup> <mml:mo stretchy="false">(</mml:mo> <mml:mi> λ </mml:mi> <mml:mo>,</mml:mo> <mml:mi> μ </mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">\mathbb {P}^{\mathbf {cc}}(\lambda ,\mu )</mml:annotation> </mml:semantics> </mml:math> </inline-formula> that (under <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="sans-serif upper N sans-serif upper S Subscript omega 1"> <mml:semantics> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="sans-serif">N</mml:mi> <mml:mi mathvariant="sans-serif">S</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mi> ω </mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:mrow> </mml:msub> <mml:annotation encoding="application/x-tex">\mathsf {NS}_{\omega _1}</mml:annotation> </mml:semantics> </mml:math> </inline-formula> precipitous + existence of <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper H Subscript theta Superscript number-sign"> <mml:semantics> <mml:msubsup> <mml:mi>H</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi> θ </mml:mi> </mml:mrow> <mml:mi mathvariant="normal"> # </mml:mi> </mml:msubsup> <mml:annotation encoding="application/x-tex">H_{\theta }^\#</mml:annotation> </mml:semantics> </mml:math> </inline-formula> for a sufficiently large regular <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="theta"> <mml:semantics> <mml:mi> θ </mml:mi> <mml:annotation encoding="application/x-tex">\theta</mml:annotation> </mml:semantics> </mml:math> </inline-formula> ) increases the second uniform indiscernible <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="bold u 2"> <mml:semantics> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">u</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> <mml:annotation encoding="application/x-tex">\mathbf {u}_2</mml:annotation> </mml:semantics> </mml:math> </inline-formula> beyond some given ordinal <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="lamda"> <mml:semantics> <mml:mi> λ </mml:mi> <mml:annotation encoding="application/x-tex">\lambda</mml:annotation> </mml:semantics> </mml:math> </inline-formula> . The forcing <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper P Superscript bold c bold c"> <mml:semantics> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="double-struck">P</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">c</mml:mi> <mml:mi mathvariant="bold">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msup> <mml:annotation encoding="application/x-tex">\mathbb {P}^{\mathbf {cc}}</mml:annotation> </mml:semantics> </mml:math> </inline-formula> shares this property with forcings defined by Claverie and Schindler [J. Symbolic Logic 74 (2009), pp. 187–200] and Ketchersid, Larson, and Zapletal [J. Symbolic Logic 72 (2007), pp. 1372–1378]. We show that <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-struck upper P Superscript bold c bold c"> <mml:semantics> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="double-struck">P</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">c</mml:mi> <mml:mi mathvariant="bold">c</mml:mi> </mml:mrow> </mml:mrow> </mml:msup> <mml:annotation encoding="application/x-tex">\mathbb {P}^{\mathbf {cc}}</mml:annotation> </mml:semantics> </mml:math> </inline-formula> is in addition <italic>strongly</italic> ssp. As a main tool we use certain natural open two player games which are of independent interest, viz. the capturing games <inline-formula content-type="math/mathml"> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="bold upper G Subscript upper M Superscript bold c bold p Baseline left-parenthesis upper X right-parenthesis"> <mml:semantics> <mml:mrow> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">G</mml:mi> </mml:mrow> <mml:mi>M</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="bold">c</mml:mi> <mml:mi mathvariant="bold">p</mml:mi> </mml:mrow> </mml:mrow> </mml:msubsup> <mml:mo stretchy="false">(</mml:mo> <mml:mi>X</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:annotation encoding="application/x-tex">\mathbf {G}^{\mathbf {cp}}_M(X)</mml

Proceedings of the American Mathematical SocietyVol. 154(4)
Centre National de la Recherche Scientifique (FR), Université Paris Cité (FR), University of Münster (DE), Institut de Mathématiques de Jussieu-Paris Rive Gauche (FR), Sorbonne Université (FR), Sorbonne Paris Cité (FR)
Openalex Percentile: Top 65%
Advanced Topology and Set Theory
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