Zobrazeno 1 - 10
of 81
pro vyhledávání: '"UNGER, SPENCER"'
Autor:
Chandgotia, Nishant, Unger, Spencer
In this paper we study the combinatorics of free Borel actions of the group $\mathbb Z^d$ on Polish spaces. Building upon recent work by Chandgotia and Meyerovitch, we introduce property $F$ on $\mathbb Z^d$-shift spaces $X$ under which there is an e
Externí odkaz:
http://arxiv.org/abs/2203.09359
In this paper we prove that from large cardinals it is consistent that there is a singular strong limit cardinal $\nu$ such that the singular cardinal hypothesis fails at $\nu$ and every collection of fewer than $\mathrm{cf}(\nu)$ stationary subsets
Externí odkaz:
http://arxiv.org/abs/1908.11145
Publikováno v:
Forum of Mathematics, Sigma 8 (2020) e10
An abstract system of congruences describes a way of partitioning a space into finitely many pieces satisfying certain congruence relations. Examples of abstract systems of congruences include paradoxical decompositions and $n$-divisibility of action
Externí odkaz:
http://arxiv.org/abs/1903.05135
Autor:
Hayut, Yair, Unger, Spencer
Publikováno v:
J. symb. log. 85 (2020) 937-959
We improve the upper bound for the consistency strength of stationary reflection at successors of singular cardinals.
Externí odkaz:
http://arxiv.org/abs/1804.11329
Autor:
Unger, Spencer
Motivated by showing that in ZFC we cannot construct a special Aronszajn tree on some cardinal greater than $\aleph_1$, we produce a model in which the approachability property fails (hence there are no special Aronszajn trees) at all regular cardina
Externí odkaz:
http://arxiv.org/abs/1702.05062
Autor:
Marks, Andrew S., Unger, Spencer T.
Publikováno v:
Ann. of Math. 186 (2017), 581-605
We give a completely constructive solution to Tarski's circle squaring problem. More generally, we prove a Borel version of an equidecomposition theorem due to Laczkovich. If $k \geq 1$ and $A, B \subseteq \mathbb{R}^k$ are bounded Borel sets with th
Externí odkaz:
http://arxiv.org/abs/1612.05833
Motivated by the goal of constructing a model in which there are no $\kappa$-Aronszajn trees for any regular $\kappa>\aleph_1$, we produce a model with many singular cardinals where both the singular cardinals hypothesis and weak square fail.
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Externí odkaz:
http://arxiv.org/abs/1604.01564
Autor:
Hayut, Yair, Unger, Spencer
We show that it is consistent, relative to $\omega$ many supercompact cardinals, that the super tree property holds at $\aleph_n$ for all $2 \leq n < \omega$ but there are weak square and a very good scale at $\aleph_{\omega}$.
Externí odkaz:
http://arxiv.org/abs/1601.07824
Autor:
Boney, Will, Unger, Spencer
We show that various tameness assertions about abstract elementary classes imply the existence of large cardinals under mild cardinal arithmetic assumptions.
Externí odkaz:
http://arxiv.org/abs/1509.01191
Autor:
Marks, Andrew, Unger, Spencer
Publikováno v:
Adv. Math. 289 (2016), 397-410
We show that every locally finite bipartite Borel graph satisfying a strengthening of Hall's condition has a Borel perfect matching on some comeager invariant Borel set. We apply this to show that if a group acting by Borel automorphisms on a Polish
Externí odkaz:
http://arxiv.org/abs/1501.01690