Giorgio Laguzzi, Heike Mildenberger, Brendan Stuber-Rousselle
{"title":"On splitting trees","authors":"Giorgio Laguzzi, Heike Mildenberger, Brendan Stuber-Rousselle","doi":"10.1002/malq.202200022","DOIUrl":"https://doi.org/10.1002/malq.202200022","url":null,"abstract":"<p>We investigate two variants of splitting tree forcing, their ideals and regularity properties. We prove connections with other well-known notions, such as Lebesgue measurablility, Baire- and Doughnut-property and the Marczewski field. Moreover, we prove that any <i>absolute</i> amoeba forcing for splitting trees necessarily adds a dominating real, providing more support to Hein's and Spinas' conjecture that <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>add</mo>\u0000 <mo>(</mo>\u0000 <msub>\u0000 <mi>I</mi>\u0000 <mi>SP</mi>\u0000 </msub>\u0000 <mo>)</mo>\u0000 <mo>≤</mo>\u0000 <mi>b</mi>\u0000 </mrow>\u0000 <annotation>$operatorname{add}(mathcal {I}_mathbb {SP}) le mathfrak {b}$</annotation>\u0000 </semantics></math>.</p>","PeriodicalId":49864,"journal":{"name":"Mathematical Logic Quarterly","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/malq.202200022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50155350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Incomparable \u0000 \u0000 \u0000 V\u0000 γ\u0000 \u0000 $V_gamma$\u0000 -degrees","authors":"Teng Zhang","doi":"10.1002/malq.202200034","DOIUrl":"https://doi.org/10.1002/malq.202200034","url":null,"abstract":"<p>In [3], Shi proved that there exist incomparable Zermelo degrees at γ if there exists an ω-sequence of measurable cardinals, whose limit is γ. He asked whether there is a size <math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>γ</mi>\u0000 <mi>ω</mi>\u0000 </msup>\u0000 <annotation>$gamma ^omega$</annotation>\u0000 </semantics></math> antichain of Zermelo degrees. We consider this question for the <math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>V</mi>\u0000 <mi>γ</mi>\u0000 </msub>\u0000 <annotation>$V_gamma$</annotation>\u0000 </semantics></math>-degree structure. We use a kind of Prikry-type forcing to show that if there is an ω-sequence of measurable cardinals, then there are <math>\u0000 <semantics>\u0000 <msup>\u0000 <mi>γ</mi>\u0000 <mi>ω</mi>\u0000 </msup>\u0000 <annotation>$gamma ^omega$</annotation>\u0000 </semantics></math>-many pairwise incomparable <math>\u0000 <semantics>\u0000 <msub>\u0000 <mi>V</mi>\u0000 <mi>γ</mi>\u0000 </msub>\u0000 <annotation>$V_gamma$</annotation>\u0000 </semantics></math>-degrees, where γ is the limit of the ω-sequence of measurable cardinals.</p>","PeriodicalId":49864,"journal":{"name":"Mathematical Logic Quarterly","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50154667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}