### 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

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

# Category Archives: Invited Talks

## ASL North American Meeting, March 2017

I gave a plenary talk at the 2017 ASL North American Meeting in Boise, March 2017. Talk Title: The current state of the Souslin problem. Abstract: Recall that the real line is that unique separable, dense linear ordering with no endpoints in … Continue reading

## MFO workshop in Set Theory, February 2017

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

## MFO workshop in Set Theory, January 2014

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

## Set Theory Programme on Large Cardinals and Forcing, September 2013

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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