Joel David Hamkins conducts research in mathematical logic, particularly set theory, with a focus on the mathematics and philosophy of the infinite.
He has explored the interaction of forcing and large cardinals and recently initiated the research topics known as set-theoretic geology, which studies how the set-theoretic universe relates to all its various ground models, and the modal logic of forcing, which explores how it relates to all its various forcing extensions.
His philosophical work on the multiverse perspective participates in the emerging debate on pluralism in the philosophy of set theory.
In addition, Hamkins has undertaken work in infinitary computability, in group theory and on the hierarchy of equivalence relations on the natural numbers under computable reducibility.

His most recent theorem is that every countable model of set theory is isomorphic to a submodel of its own constructible universe.

Professor Hamkins earned his Ph.D at the University of California at Berkeley in 1994, and holds a permanent position as Professor at The City University of New York, at the Graduate Center of CUNY and at the College of Staten Island of CUNY.

Personal website

# Recent and upcoming talks by Joel David Hamkins

## This Week in Logic at CUNY

Computational Logic Seminar Tuesday, May 7, 2013 2:00 pm Graduate Center, rm. 3209 Speaker: Yoram Moses Israel Institute of Technology – Technion Title: Knowledge and the Passage of Time This talk will discuss how knowledge, nested knowledge, and common knowledge are gained in the presence of clocks and time bound information. continue reading…

## This Week in Logic at CUNY

Computational Logic Seminar Tuesday, April 30, 2013 2:00 pm rm. 3209, Graduate Center CUNY Speaker: Melvin Fitting Lehman College, CUNY Graduate Center Title: Realization Implemented Justification logics are connected to modal logics via realization theorems. continue reading…

## 25/Mar/2013: Simon Thomas and Joel Hamkins

Rutgers Logic Seminars Spring 2013 Rooms 423 & 705, Hill Center Descriptive Set Theory Seminar Hill 423 Monday Mar 25th, 3:20-4:40 pm Simon Thomas, Rutgers Invariant random subgroups VI Rutgers Logic Seminar Hill 705 Monday Mar 25th, 5:00-6:20 pm Joel Hamkins, CUNY Pluralism in mathematics: the multiverse view in set theory and the question of whether every mathematical statement has a definite truth value Abstract: I shall describe the debate on pluralism in the philosophy of set theory, specifically on the question of whether every mathematical and set-theoretic assertion has a definite truth value. continue reading…

## This Week in Logic at CUNY

Models of PA Wednesday, February 27, 2013 6:45 pm Speaker: Erez Shochat St. Francis College Title: Introduction to interstices and intersticial gaps II   Set theory seminar Friday, March 1, 2013 10:00 am Speaker: Joel David Hamkins The City University of New York Title: The omega one of chess This talk will be based on my recent paper with C. continue reading…

## This Week in Logic at CUNY

Computational Logic Seminar January 29, Time 2:00 – 4:00 PM, Room 3209 Speaker: Sergei Artemov, CUNY Graduate Center Title: Definitive solutions of strategic games Abstract: In his dissertation of 1950, Nash based his concept of solution to a game on the principles that “a rational prediction should be unique, that the players should be able to deduce and make use of it.” In this paper, we address the issue of when Nash expectations of a definitive solution hold and whether the Nash Equilibrium (NE) solution concept is a match for such definitive solutions. continue reading…

## This Week in Logic at CUNY

November 27, Time 2:00 – 4:00 PM, Room 3309 Speaker: Melvin Fitting, CUNY Title: Possible world semantics for first order LP Abstract: Propositional Justification Logics are modal-like logics in which the usual necessity operator is split into a family of more complex terms called justifications. continue reading…

## Joel Hamkins: The countable models of set theory are linearly pre-ordered by embeddability

Rutgers Logic Seminars Fall 2012 Room 705, Hill Center Rutgers Logic Seminar Monday Nov 19th, 5:00-6:20 pm Joel Hamkins, CUNY The countable models of set theory are linearly pre-ordered by embeddability Descriptive Set Theory Seminar Monday Nov 19th, 3:20-4:40 pm No seminar this week continue reading…

## This Week in Logic at CUNY

Computational Logic Seminar Time 2:00 – 4:00 PM, September 11, Room 3309 Can Baskent, IHPST, Université Paris 1 Panthéon-Sorbonne Some Logical Approaches to Lakatos’s ‘Proofs and Refutations’ Abstract. Lakatos’s seminal work ‘Proofs and Refutations’ presents a rational analysis of theorem improvement. continue reading…

## This Week in Logic at CUNY

Computational Logic Seminar September 4, Time 2:00 – 4:00 PM, Room 3309. Speaker: Tudor Protopopescu (Graduate Center) Title: Discovering Knowability: A Semantic Analysis (a joint work with S. Artemov, just appeared in Synthese) Abstract: We provide a semantic analysis of the well-known knowability paradox stemming from the Church-Fitch observation that the meaningful knowability principle all truths are knowable, when expressed as a bi-modal principle F -> <>KF, yields an unacceptable omniscience property all truths are known. continue reading…

## 24/Aug/2012: Joel David Hamkins, and Lajos Soukup

11:00–12:00 Fields institute, Room 210 Speaker:  Joel David Hamkins (The City University of New York) Title: Every countable model of set theory embeds into its own constructible universe. Abstract:  I shall give an account of my recent theorem showing that every countable model of set theory $M$, including every well-founded model, is isomorphic to a submodel of its own constructible universe. continue reading…