### Archives

### Recent blog posts

- Prikry forcing may add a Souslin tree June 12, 2016
- The reflection principle $R_2$ May 20, 2016
- Prolific Souslin trees March 17, 2016
- Generalizations of Martin’s Axiom and the well-met condition January 11, 2015
- Many diamonds from just one January 6, 2015
- Happy new jewish year! September 24, 2014
- Square principles April 19, 2014
- Partitioning the club guessing January 22, 2014

### Keywords

Knaster stationary reflection P-Ideal Dichotomy PFA(S)[S] Kurepa Hypothesis HOD Erdos-Hajnal graphs Fast club Forcing Commutative cancellative semigroups Prikry-type forcing Whitehead Problem Forcing Axioms approachability ideal Cardinal Invariants xbox Hedetniemi's conjecture Parameterized proxy principle Singular coﬁnality stationary hitting OCA Selective Ultrafilter Fat stationary set Antichain Aronszajn tree Shelah's Strong Hypothesis PFA polarized partition relation Slim tree Hindman's Theorem Axiom R Ostaszewski square S-Space Ascent Path square Almost Souslin Foundations Cardinal function Minimal Walks Non-saturation Martin's Axiom sap tensor product graph weak diamond diamond star L-space Reduced Power projective Boolean algebra Poset Uniformization Small forcing Diamond middle diamond Large Cardinals Rado's conjecture very good scale 05D10 coloring number Club Guessing Square-Brackets Partition Relations Chromatic number Microscopic Approach Universal Sequences Rainbow sets Generalized Clubs Jonsson cardinal incompactness Singular cardinals combinatorics Successor of Singular Cardinal Cohen real ccc 05A17 Constructible Universe Almost-disjoint famiy b-scale Hereditarily Lindelöf space Almost countably chromatic Sakurai's Bell inequality Singular Cofinality Successor of Regular Cardinal Coherent tree free Boolean algebra 20M14 Weakly compact cardinal 11P99 weak square reflection principles Singular Density Stevo Todorcevic Fodor-type reflection Chang's conjecture Dushnik-Miller Mandelbrot set Rock n' Roll Partition Relations Erdos Cardinal Absoluteness Prevalent singular cardinals Souslin Tree

# Category Archives: Invited Talks

## 2017 Workshop in Set Theory, Oberwolfach

I gave an invited talk at the Set Theory workshop in Obwerwolfach, February 2017. Talk Title: Coloring vs. Chromatic. Abstract: In a joint work with Chris Lambie-Hanson, we study the interaction between compactness for the chromatic number (of graphs) and … Continue reading

Posted in Invited Talks
Tagged Chromatic number, coloring number, incompactness, stationary reflection
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## Set Theory and its Applications in Topology, September 2016

I gave an invited talk at the Set Theory and its Applications in Topology meeting, Oaxaca, September 11-16, 2016. The talk was on the $\aleph_2$-Souslin problem. If you are interested in seeing the effect of a jet lag, the video is … Continue reading

## P.O.I. Workshop in pure and descriptive set theory, September 2015

I gave an invited talk at the P.O.I Workshop in pure and descriptive set theory, Torino, September 26, 2015. Title: $\aleph_3$-trees. Abstract: We inspect the constructions of four quite different $\aleph_3$-Souslin trees.

## The Apter-Gitik birthday conference, May 2015

I give an invited (blackboard) talk at the Apter-Gitik birthday conference, Carnegie Mellon University, May 30-31 2015. Title: Putting a diamond inside the square. Abstract: By a 35-year-old theorem of Shelah, $\square_\lambda+\diamondsuit(\lambda^+)$ does not imply square-with-built-in-diamond_lambda for regular uncountable cardinals … Continue reading

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## Forcing and its Applications Retrospective Workshop, April 2015

I gave an invited talk at Forcing and its Applications Retrospective Workshop, Toronto, April 1st, 2015. Title: A microscopic approach to Souslin trees constructions Abstract: We present an approach to construct $\kappa$-Souslin trees that is insensitive to the identity of … Continue reading

Posted in Invited Talks
Tagged Microscopic Approach, Parameterized proxy principle, Souslin Tree
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## INFTY Final Conference, March 2014

I gave an invited talk at the INFTY Final Conference meeting, Bonn, March 4-7, 2014. [Curiosity: Georg Cantor was born March 3, 1845] Title: Same Graph, Different Universe. Abstract: In a paper from 1998, answering a question of Hajnal, Soukup … Continue reading

## 2014 Workshop in Set Theory, Oberwolfach

I gave an invited talk at the Set Theory workshop in Obwerwolfach, January 2014. Talk Title: Complicated Colorings. Abstract: If $\lambda,\kappa$ are regular cardinals, $\lambda>\kappa^+$, and $E^{\lambda}_{\ge\kappa}$ admits a nonreflecting stationary set, then $\text{Pr}_1(\lambda,\lambda,\lambda,\kappa)$ holds. Downloads:

## Mathematics Colloquium, Bar-Ilan University, November 2013

I gave a colloquium talk at Bar-Ilan University on November 10, 2013. Title: Forcing as a tool to prove theorems Abstract: Paul Cohen celebrated solution to Hilbert’s first problem showed that the Continuum Hypothesis is independent of the usual axioms of … Continue reading

## 2013 Set Theory Programme on Large Cardinals and Forcing

I gave an invited talk at the Large Cardinals and Forcing meeting, Erwin Schrödinger International Institute for Mathematical Physics, Vienna, September 23–27, 2013. Talk Title: Hedetniemi’s conjecture for uncountable graphs Abstract: It is proved that in Godel’s constructible universe, for … Continue reading

Posted in Invited Talks
Tagged Almost countably chromatic, Chromatic number, Hedetniemi's conjecture
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## 2012 North American Annual Meeting of the ASL

I gave a special session talk at the ASL 2012 North American Annual Meeting (Madison, March 31–April 3, 2012). Talk Title: The extent of the failure of Ramsey’s theorem at successor cardinals. Extended abstract: Ramsey’s theorem asserts that for every coloring … Continue reading

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