Author Archives: Assaf Rinot

A new model for all C-sequences are trivial

Joint work with Zhixing You and Jiachen Yuan. Abstract. We construct a model in which all C-sequences are trivial, yet there exists a κ-Souslin tree with full vanishing levels. This answers a question from a previous paper, and provides an … Continue reading

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MFO workshop in Set Theory, January 2025

I gave an invited talk at the Set Theory meeting in Obwerwolfach, January 2025. Talk Title: Non-structure theorems for higher Aronszajn lines. Abstract: An ω1-Countryman line is an uncountable linear order  L such that L2 (with the pointwise ordering) is … Continue reading

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Walks on uncountable ordinals and non-structure theorems for higher Aronszajn lines

Joint work with Tanmay Inamdar. Abstract. We investigate global structural properties of linear orders of a fixed infinite size. It is classical that the countable linear orders and the continuum-sized orders exhibit contrasting behaviours. Modern results show that strong extensions … Continue reading

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Ketonen’s question and other cardinal sins

Joint work with Zhixing You and Jiachen Yuan. Abstract. Intersection models of generic extensions obtained from a commutative projection systems of notions of forcing has recently regained interest, especially in the study of descriptive set theory. Here, we show that … Continue reading

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120 Years of Choice, July 2024

I gave an invited talk at the 120 Years of Choice conference, July 2024. Talk Title: Mathematician’s best friend Abstract: Jensen’s diamond is a very useful postulate. It is well-known that it implies the continuum hypothesis, that it is equivalent … Continue reading

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A model for global compactness

Joint work with Sittinon Jirattikansakul and Inbar Oren. Abstract. In a classical paper by Ben-David and Magidor, a model of set theory was exhibited in which ω+1 carries a uniform ultrafilter that is θ-indecomposable for every uncountable θ<ω. In this … Continue reading

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Diamond on Kurepa trees

Joint work with Ziemek Kostana and Saharon Shelah. Abstract. We introduce a new weak variation of diamond that is meant to only guess the branches of a Kurepa tree. We demonstrate that this variation is considerably weaker than diamond by … Continue reading

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Proxy principles in combinatorial set theory

Joint work with Ari Meir Brodsky and Shira Yadai. Abstract. The parameterized proxy principles were introduced by Brodsky and Rinot in a 2017 paper as new foundations for the construction of κ-Souslin trees in a uniform way that does not … Continue reading

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Squares, ultrafilters and forcing axioms

Joint work with Chris Lambie-Hanson and Jing Zhang. Abstract. We study the interplay of the three families of combinatorial objects or principles. Specifically, we show the following. Strong forcing axioms, in general incompatible with the existence of indexed squares, can … Continue reading

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May the successor of a singular cardinal be Jonsson?

Abstract: We collect necessary conditions for the successor of a singular cardinal to be Jónsson.

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