**CUNY Graduate Center**

**Room 4214.03**

**Wednesdays 6:30pm-8pm**

**Organized by Roman Kossak and Athar Abdul-Quader **

**Calendar**

**May 31**

**8:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Tin Lok Wong**
National University of Singapore

**Another quantifier-elimination result in arithmetic under negated induction**

**Abstract**

**May 24**

**2:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Laurence Kirby**
Baruch College

**The winding road to mathematical independence results for PA**

**Abstract**

**May 17**

**2:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Ken McAloon**
Brooklyn College

**E Pluribus Unum**

**Abstract**

**May 10**

**10:00am** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Saeed Salehi**
University of Tabriz

*ω*-Consistency: Gödel’s “much weaker” notion of soundness

**Abstract**

**May 3**

**2:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Dino Rossegger**
UC Berkeley and TU Wien

**The structural complexity of models of PA**

**Abstract**

**April 26**

**2:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Michał Godziszewski**
University of Vienna

**Modal Quantifiers, Potential Infinity, and Yablo sequences**

**Abstract**

**April 19**

**2:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Roman Kossak**
CUNY

**Absolute undefinability in arithmetic**

**Abstract**

**April 12**

**2:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Thomas Ferguson**
University of Amsterdam and University of St. Andrews

**Models of relevant arithmetic: Part II**

**Abstract**

**March 29**

**8:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Erez Shochat**
St. Francis College

**A Survey on the Automorphism Groups of Countable (Boundedly) Recursively Saturated Models of PA**

**Abstract**

**March 22**

**2:00pm** NY time

**Virtual** (email Victoria Gitman for meeting id)

**Ermek Nurkhaidarov**
Penn State Mont Alto

**Generic Automorphisms**

**Abstract**

**March 15**

**The seminar will take place virtually at 2pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Thomas Ferguson**
University of Amsterdam and University of St. Andrews

**Models of Relevant Arithmetic**

**Abstract**

**January 17**

**The seminar will take place virtually at 2pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Mauro di Nasso**
Università di Pisa

**Nonstandard natural numbers in arithmetic Ramsey Theory and topological dynamics: Part II**

**Abstract**

**January 10**

**The seminar will take place virtually at 2pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Albert Visser**
Utrecht University

**Interpreters as a species of Consistoids**

**Abstract**

**December 13**

**Cezary Cieśliński**
University of Warsaw

**On the principle of disjunctive correctness**

**Abstract**

**December 6**

**Bartosz Wcisło**
Polish Academy of Sciences

**Model theoretic characterizations of truth: Part II**

**Abstract**

**November 29**

**Mateusz Łełyk**
University of Warsaw

**Model theoretic characterizations of truth: Part I**

**Abstract**

**November 22**

**Mauro di Nasso**
Università di Pisa

**Nonstandard natural numbers in arithmetic Ramsey Theory and topological dynamics**

**Abstract**

**November 15**

**Rasmus Blanck**
University of Gothenburg

**Incompleteness results for arithmetically definable extensions of strong fragments of PA**

**Abstract**

**November 1**

**Fedor Pakhomov**
Ghent University

**Finitely Axiomatized Theories Lack Self-Comprehension**

**Abstract**

**April 27**

**Dave Marker**
University of Illinois at Chicago

**Real closures of $\omega_1$-like models of PA**

**Abstract**

**April 20**

**Andrés Cordón Franco**
Universidad de Sevilla

**Induction and collection up to definable elements: calibrating the strength of parameter-free $\Delta_n$-minimization.**

**Abstract**

**April 13**

**Roman Kossak**
CUNY

**Automorphisms, Jónsson Models, and Satisfaction Classes**

**Abstract**

**April 6**

**The seminar will take place virtually at 7pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Zachiri McKenzie**
Zhejiang University

**Topless powerset preserving end-extensions and rank-extensions of countable models of set theory**

**Abstract**

**March 30**

**Paola d’Aquino**
Università della Campania -“L. Vanvitelli”

**Residue rings of models of Peano Arithmetic**

**Abstract**

**March 23**

**Mateusz Łełyk**
University of Warsaw

**Nonequivalent axiomatizations of PA and the Tarski Boundary: Part III**

**Abstract**

**March 16**

**Mateusz Łełyk**
University of Warsaw

**Nonequivalent axiomatizations of PA and the Tarski Boundary: Part II**

**Abstract**

**March 9**

**Damir Dzhafarov**
University of Connecticut

**Reduction games, provability, and compactness**

**Abstract**

**March 2**

**The seminar will take place virtually at 7pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Ali Enayat**
University of Gothenburg

**PA with a class of indiscernibles**

**Abstract**

**February 23**

**Corey Switzer**
University of Vienna

**Independence in PA: The Method of $(\mathcal L, n)$-Models**

**Abstract**

**February 16**

**Mateusz Łełyk**
University of Warsaw

**Nonequivalent axiomatizations of ${\rm PA}$ and the Tarski Boundary**

**Abstract**

**February 9**

**Leszek Kołodziejczyk**
University of Warsaw

**An isomorphism theorem for models of Weak Kőnig's Lemma without induction**

**Abstract**

**February 2**

**James Walsh**
Cornell University

**Reducing omega-model reflection to iterated syntactic reflection**

**Abstract**

**December 9**

**The seminar will take place virtually at 3pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Konrad Zdanowski**
Cardinal Stefan Wyszynski University in Warsaw

**Truth predicate for $\Delta_0$ formulas and PSPACE computations**

**Abstract**

**November 11**

**The seminar will take place virtually at 12pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Joel David Hamkins**
Oxford University

**Continuous models of arithmetic**

**Abstract**

**November 4**

**The seminar will take place virtually at 3pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Victoria Gitman**
CUNY

**A model of second-order arithmetic satisfying AC but not DC: Part II**

**Abstract**

**October 28**

**The seminar will take place virtually at 3pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Victoria Gitman**
CUNY

**A model of second-order arithmetic satisfying AC but not DC**

**Abstract**

**October 21**

**The seminar will take place virtually at 7pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Roman Kossak**
CUNY

**Types, gaps, and pairs of models of PA: Part III**

**Abstract**

**October 14**

**Roman Kossak**
CUNY

**Types, gaps, and pairs of models of PA: Part II**

**Abstract**

**October 7**

**Roman Kossak**
CUNY

**Types, gaps, and pairs of models of PA**

**Abstract**

**September 30**

**Leszek Kołodziejczyk**
University of Warsaw

**Ramsey's Theorem over $\mathrm{RCA}^*_0$: Part II**

**Abstract**

**September 16**

**The seminar will take place virtually at 5pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Sam Coskey**
Boise State University

**Classification of countable models of ZFC**

**Abstract**

**September 9**

**Saeideh Bahrami**
Institute for Research in Fundamental Sciences, Tehran

**Fixed Points of Initial Self-Embeddings of Models of Arithmetic**

**Abstract**

**September 2**

**Petr Glivický**
Universität Salzburg

**The $\omega$-iterated nonstandard extension of $\mathbb{N}$ and Ramsey combinatorics**

**Abstract**

**August 26**

**The seminar will take place virtually at 12pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Emil Jeřábek**
Czech Academy of Sciences

**Feasible reasoning with arithmetic operations**

**Abstract**

**August 19**

**Leszek Kołodziejczyk**
University of Warsaw

**Ramsey's Theorem over $\mathrm{RCA}^*_0$**

**Abstract**

**August 12**

**Athar Abdul-Quader**
Purchase College

**CP-genericity and neutrality**

**Abstract**

**July 29**

**Kameryn Williams**
University of Hawai‘i at Mānoa

**End-extensions of models of set theory and the $\Sigma_1$ universal finite sequence**

**Abstract**

**July 22**

**The seminar will take place virtually at 8pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Tin Lok Wong**
National University of Singapore

**Properties preserved in cofinal extensions**

**Abstract**

**July 15**

**Mateusz Łełyk**
University of Warsaw

**Partial Reflection over Uniform Disquotational Truth II**

**Abstract**

**July 8**

**Corey Switzer**
CUNY

**Axiomatizing Kaufmann models in strong logics**

**Abstract**

**July 1**

**Zachiri McKenzie**

**Initial self-embeddings of models of set theory: Part II**

**Abstract**

**June 24**

**Bartosz Wcisło**
Polish Academy of Sciences

**Tarski boundary III**

**Abstract**

**June 17**

**Mateusz Łełyk**
University of Warsaw

**Partial Reflection over Uniform Disquotational Truth**

**Abstract**

**June 3**

**Zachiri McKenzie**

**Initial self-embeddings of models of set theory: Part I**

**Abstract**

**May 27**

**Bartosz Wcisło**
Polish Academy of Sciences

**Tarski boundary II**

**Abstract**

**May 20**

**Seminar cancelled**

There is no seminar today.

**May 13**

**Laurence Kirby**
CUNY

**Bounded finite set theory**

**Abstract**

**May 6**

**Ali Enayat**
University of Gothenburg

**The Barwise-Schlipf characterization of recursive saturation of models of PA: Part II**

**Abstract**

**April 29**

**Ali Enayat**
University of Gothenburg

**The Barwise-Schlipf characterization of recursive saturation of models of PA: Part I**

**Abstract**

**April 22**

**Corey Switzer**
CUNY

**Hanf Numbers of Arithmetics**

**Abstract**

**April 15**

**Wei Wang**
Institute of Logic and Cognition, Sun Yat-sen University

**Non-standard models of arithmetic and their standard systems**

**Abstract**

**April 1**

**The seminar will take place virtually at 8pm US Eastern Standard Time. Please email Victoria Gitman for meeting id.**

**Whan Ki Lee**
CUNY

**Solid bases and AH-sets**

**Abstract**

**March 4**

**Alexander Van Abel**
CUNY

**Omitting Classes of Elements**

**Abstract**

**February 26**

**Athar Abdul-Quader**
Purchase College

**Pentagon III**

**Abstract**

**February 19**

**James Geiser**

**Soundness and the Gödel Undecidability Theorem**

**Abstract**

**February 5**

**Athar Abdul-Quader**
Purchase College

**The pentagon saga continues**

**Abstract**