STEFFEN LEMPP

Office Address

Department of Mathematics
University of Wisconsin
480 Lincoln Drive
Madison , WI 53706-1325
USA

Email/Skype/Phone/Fax

Email: @math.wisc.edu">lemppmath.wisc.edu
Skype: steffen.lempp
Office phone: +1-608-263-1975
Department phone: +1-608-263-3053
Fax: +1-608-263-8891
(Please note that I do not regularly monitor the answering machine of my office phone, so if you want to reach me quickly, email works best.)

Office and office hours during semester

I will be on sabbatical till early January 2024.

Course taught in spring 2024

Math 773: Computability Theory: Course information (to be announced)

Note to current and prospective graduate students

Since I will retire in December 2024, I will not take on new graduate students (except as co-advisor).
I encourage any student interested in logic to contact my wonderful colleagues in logic.

Logic seminars around the Midwest

UW Logic Seminar
UW Graduate Logic Seminar
UW CS Theory Seminar
Midwest Computability Seminar (a joint seminar of the University of Wisconsin-Madison, the University of Chicago and the University of Notre Dame, held once or twice a semester on the University of Chicago campus)
Midwest Model Theory Seminar (a joint seminar of the University of Wisconsin-Madison, the University of Illinois-Chicago and the University of Notre Dame, held once a semester on the University of Illinois at Chicago campus)
University of Chicago Logic Seminar
Louise Hay Logic Seminar, University of Illinois-Chicago
University of Illinois-Chicago Logic Seminar
Notre Dame Logic Seminar
Indiana University Logic Seminar

Conferences I plan to attend

July 10-14, 2023: 16th International Conference on Computability, Complexity and Randomness (CCR), Lake Kochel, Germany
July 24-28, 2023: CiE 2023 (Computability in Europe), Batumi State University, Georgia (hybrid, see Call for Papers)
September-December 2023: sabbatical semester at Technical University of Vienna, Austria

Online logic seminars worldwide

Computability Theory and Applications Online Seminar (organized by Vasco Brattka, Damir Dzhafarov, Katia Fokina, Noam Greenberg, Takayuki Kihara, Ludovic Patey, Arno Pauly and Linda Westrick, requires one-time on-line registration, with many recordings on youtube channel)
Logic Seminars (list of research seminars in sciences created by Edgar Costa and David Roe; you can filter for math and then logic)
Logic Supergroup (alliance of around 20 logic groups worldwide, requires registration with organizers)
Logicians in Quarantine (organized by Bruno Lopes and Petrucio Viana, Universidade Federal Fluminense, Rio de Janeiro, Brazil; site is in Portuguese, and times listed are local to Brazil, but titles (and talks) are often in English, and links to talks are provided)
Online Logic Seminar (join here, organized by Wesley Calvert, Southern Illinois University, Carbondale; no registration needed)
Online seminars and talks in Logic (list maintained by Miguel Moreno, University of Vienna)

Other conferences of interest to logicians

June 5-9, 2023: European Logic Colloquium 2023, University of Milan, Italy
June 12-July 7, 2023: Workshop "From omega to Omega", National University of Singapore
October 2-6, 2023: 5th Workshop on Digitalization and Computable Models (WDCM-2023), Nazarbayev University, Astana, Kazakhstan (hybrid)

Web pages from past conferences and special sessions I have co-organized

Oberwolfach 2012 Workshop in Computability Theory: program and slides
ASL 2012 North American Annual Meeting, University of Wisconsin, Madison
AMS Sectional Meeting, Special Session in Computability: slides, Loyola University of Chicago, October 2015
Dagstuhl 2017 Seminar in Computability Theory: schedule and slides
Oberwolfach 2018 Workshop in Computability Theory: schedule and slides
Special session in computability theory, CiE 2021, Ghent
Special session in computability theory, European Logic Colloquium 2021, Poznań

My research interests

My primary research interest is computability in its various aspects, both in classical computability theory, in particular degree structures, and in applications of computability to model theory, algebra, proof theory, and computer science.

Some particular problems I have been working on, or would be interested in working on again, include

algebraic structures of, and decidability of fragments of theories of, degree structures (esp. the c.e. Turing degrees, the d.c.e. and n-c.e. Turing degrees, the global enumeration degrees and the Σ⁰₂-enumeration degrees),
computable numberings of families of sets, esp. finite families of c.e. sets,
c.e. and other equivalence relations and their structure,
computable algebraic structures, such as linear orders, Boolean algebras, and groups,
characterization of computable algebraic structures by classical invariants (e.g., Ketonen invariants and Ulm invariants),
degrees of models of א₁-categorical theories, and more generally of trivial theories of finite Morley rank,
proof-theoretical strength of combinatorial principles related to Ramsey's Theorem for pairs, and
equivalence of Martin-Löf randomness with other notions of randomness (in particular Kolmogorov-Loveland randomness).

My curriculum vitae, bibliography, and mathematical genealogy

My CV
My math genealogy (collated by my former student Chris Alfeld)

My publications on line

Titles, abstracts, and pdf files

Lobachevskii Journal of Mathematics

In March 2015, I became one of the editors for this journal established by the Russian Academy of Sciences and Kazan State University and distributed by Springer-Verlag.

Submissions in mathematical logic, especially in computability theory and its applications, can be sent directly to me by email at @math.wisc.edu">lemppmath.wisc.edu. Before submission, be sure to consult the instructions on how to prepare your manuscript.

Professional Organizations

Research databases of interest to logicians

AMS 2020 Mathematics Subject Classifications
arXiv.org in logic (open-access database of papers in math and science, maintained by Cornell University)
Bibliography of General Theory of Computability (maintained by Igor A. Lavrov, contains also many papers in Russian)
Bibliography on Boolean algebras (maintained by Don Monk, University of Colorado)
computability.org (online resource for computability theorists maintained by Damir Dzhafarov, University of Connecticut-Storrs)
The Computability Menagerie (a diagram of known implications and non-implications about degree classes, maintained by Joe Miller)
Computability theory (list server maintained by Bjørn Kjos-Hanssen, University of Hawai'i-Mānoa)
Computer Science Bibliography (maintained by the University of Trier, Germany)
European Mathematical Information Service (EMIS) (a central portal for electronic math resources in Europe)
Forking and Dividing: Map of the Universe (maintained by Gabe Conant)
FRG: Collaborative Research: Computability Theoretic Aspects of Combinatorics
Göttinger DigitalisierungsZentrum (GDZ) (an open-access database of many resources in mathematics, mainly from German-speaking and Eastern European countries, maintained by the University of Göttingen, e.g., Algebra and Logic (in Russian))
JSTOR (Journal Storage, maintained by the Carnegie Mellon Foundation, requires subscription by your institution, or ASL membership)
Lattice Drawing (maintained by Ralph Freese, University of Hawai'i-Mānoa)
Logic Mailing List (maintained by the Bonn Mathematical Logic Group)
Math-Net.Ru: All-Russian Mathematical Portal (maintained by Steklov Mathematical Institute of the Russian Academy of Sciences)
Math journal price surveys (maintained by Ulf Rehmann, Bielefeld, Germany)
Mathematical Logic around the world (maintained by Martin Goldstern, Technical University of Vienna, Austria)
Mathematics Genealogy Project (maintained by North Dakota State University)
Mathematics on the Web (including foreign-language mathematical dictionaries, maintained by the AMS)
Mathoverflow in logic (a place for mathematicians to ask and answer questions)
Open Logic Project (an open source logic text in adjustable modules, with some prebuilt versions (instigated by Richard Zach)
Project Euclid (a non-profit journal database maintained by Cornell University and primarily funded by the Mellon Foundation)
Proof Theory Blog
Research groups in logic and theoretical computer science (maintained by Anton Setzer, Swansea, Wales)
Shelah Archive (maintained by Technical University of Vienna, Austria)
zbMATH (Zentralblatt search for math papers;free access starting January 1, 2021!)
Zoo Viewer (non-implications in various arease of computability theory, maintained by Damir Dzhafarov and Ludovic Patey)

Job openings I happen to hear of

Epic Systems Corp., Verona, Wisconsin
Marie Curie Fellowships (funded by the European Union)
(non-tenure track) Peng Tsu Ann Assistant Professorship, National University of Singapore
Logic postdoc at Nanjing University, China
Tenure-track position at Nanjing University, China
Odysseus Program (both senior and junior visiting positions funded by the Research Foundation - Flanders of Belgium)
Simons-Berkeley Research Fellowships, University of California-Berkeley
Postdoc at Technical University of Vienna, Austria
Lecturer position at University of Leeds, England
Logic postdoc at University of Udine, Italy
University of Wisconsin-Madison

Information on special Ph. D. and Master's Programs in Logic

Master of Logic, University of Amsterdam, The Netherlands
Master in Pure and Applied Logic, University of Barcelona, Spain
Ph.D. in Logic and the Methodology of Science, University of California-Berkeley
Master's in Logic and Theory of Science, Eötvös University, Budapest, Hungary
Pure and Applied Logic (PAL) program, Carnegie Mellon University, Pittsburgh, Pennsylvania
Ph.D. in Logic and the Foundations of Mathematics, University of Notre Dame, Indiana
Master in Logic and Philosophy of Science, Ludwig-Maximilian University of Munich, Germany
University of Wisconsin-Madison ("special committee degree" information for "build-your-own-PhD program" information, e.g., in "logic")

Summer Schools in Logic for Undergraduate and Graduate Students

IMS Graduate Summer School in Logic, National University of Singapore (June 26-July 14, 2023)

ASL Committee on Translations

Our committee invites suggestions for books, monographs, and papers to be translated into and from English. The criteria for translation are high quality of material presented, lack of an equivalent text in the language to be translated into, and marketability of the translated text. We invite especially submissions from authors and from the advisors of theses.

If you are an author of a book that will appear soon (as a new book or in a revised edition), we encourage you to discuss with your publisher the option of retaining the copyright for your book in translation into other languages! This is best done before you sign the final contract. Of course, it is up to you, but you should keep this option in mind.

Please send your suggestions to one of the committee members: Andrés Villaveces (Universidad Nacional de Colombia, Bogotá, Colombia), Zhaokuan Hao (Fudan University, Shanghai, China), Iskander Kalimullin (Kazan Federal University, Russia), Hiroakira Ono (Japan Advanced Institute of Science and Technology (JAIST), Ishikawa, Japan), Todor Tsankov (University of Lyon 1, France), or me (@math.wisc.edu">lemppmath.wisc.edu).

Information for Russian-speaking Logicians

The ASL Committee on Translations offers a Russian translation of Bruno Poizat's
"Cours de théorie des modèles" ("A Course in Model Theory") for free download.

I also administer the program of the Association for Symbolic Logic (ASL) offering

free subscriptions to
the Journal of Symbolic Logic and the Bulletin of Symbolic Logic
to university libraries in the former Warsaw Pact countries
which are on the World Bank List of developing economies.

For more information about this program, click here for information in English or in Russian.

Home pages of some other logicians

(If the family name of a person is ambiguous (in my humble opinion), then it is listed below in all capital letters.)

Uri Andrews, University of Wisconsin-Madison
Andy Arana, University of Lorraine, Nancy and Paris. France
Marat Arslanov, Kazan Federal University, Russia
Matthias Aschenbrenner, University of Vienna, Austria
Jeremy Avigad, Carnegie Mellon University
Serikzhan Badaev, Kazakh National University, Almaty
John Baldwin, University of Illinois-Chicago
George Barmpalias, Chinese Academy of Sciences, Beijing, China
Kolya Bazhenov, Sobolev Institute of Mathematics, Novosibirsk, Russia
Verónica Becher, University of Buenos Aires, Argentina
Itaï BEN YAACOV, University of Lyon, France
Michael Benedikt, Oxford University, England
Laurent Bienvenu, University of Bordeaux, France
Steve Binns, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
Vasco Brattka, University of the Army, Munich, Germany
Katie Brodhead, Florida State University, Panama City
Jin-Yi Cai, University of Wisconsin-Madison
Wesley Calvert, Southern Illinois University, Carbondale
Doug Cenzer, University of Florida, Gainesville
Artem Chernikov, University of Los Angeles-California
Peter Cholak, University of Notre Dame
Chi Tat Chong, National University of Singapore
Chris Conidis, City University of New York-College of Staten Island
Barbara Csima, University of Waterloo, Ontario, Canada
Arman Darbinyan, Texas A&M University, College Station, Texas
Natasha Dobrinen, University of Notre Dame, Indiana
Rod Downey, Victoria University of Wellington, New Zealand
Damir Dzhafarov, University of Connecticut-Storrs
Marat Faizrahmanov, Kazan Federal University, Russia
Katia Fokina, Vienna University of Technology, Austria
Johanna Franklin, Hofstra University, Hempstead, New York
Jim Freitag, University of Illinois-Chicago
Harvey Friedman, Ohio State University, Columbus
Sy David Friedman, Kurt Gödel Research Center for Mathematical Logic (KGRC), Vienna, Austria
Andrey Frolov, Kazan Federal University, Russia
Hristo Ganchev, Sofia University, Bulgaria
Su GAO, Nankai University, Tianjin, China
Peter Gerdes, Indiana University, Bloomington
Jun Le GOH, National University of Singapore
Isaac Goldbring, University of California-Irvine
Sergey Goncharov, Siberian Branch of the Russian Academy of Sciences and Novosibirsk State University, Russia
Noam Greenberg, Victoria University of Wellington, New Zealand
Valentina Harizanov, George Washington University, Washington, D.C.
Matthew Harrison-Trainor, University of Illinois-Chicago
Denis Hirschfeldt, University of Chicago, Illinois
Jeff Hirst, Appalachian State University, Boone, North Carolina
Meng-Che ("Turbo") Ho, Claifornia State University, Northridge
Steve Jackson, University of North Texas, Denton
Carl Jockusch, University of Illinois at Urbana-Champaign
Asher Kach, Google-Chicago
Iskander Kalimullin, Kazan Federal University, Russia
Jerry Keisler, University of Wisconsin-Madison
Bakhadyr Khoussainov, University of Auckland, New Zealand and University of Electronic Science and Technology of China, Chengdu, China
Takayuki Kihara, Nagoya University, Japan
Byunghan Kim, Yonsei University, Seoul, South Korea
Bjørn Kjos-Hanssen, University of Hawai'i-Mānoa
Ulrich Kohlenbach, University of Darmstadt, Germany
Leszek Kołodziejczyk, University of Warsaw, Poland
Chris Laskowski, University of Maryland-College Park
Andy Lewis-Pye, London School of Economics, England
Jack Lutz, Iowa State University, Ames
Maryanthe Malliaris, University of Chicago, Illinois
Alberto Marcone, University of Udine, Italy
Dave Marker, University of Illinois-Chicago
Andrew Marks, University of California-Los Angeles
Tim McNicholl, Iowa State University, Ames
Sasha Mel'nikov, Victoria University of Wellington, New Zealand
Joe Mileti, Grinnell College, Grinnell, Iowa
Arnie Miller, University of Wisconsin-Madison
Joe Miller, University of Wisconsin-Madison
Russell Miller, Queens College, New York City
Benoît Monin, University of Paris-Est Créteil, France
Antonio Montalbán, University of California-Berkeley
Andrey Morozov, Novosibirsk State University and Russian Academy of Sciences, Russia
Carl Mummert, Marshall University, Huntington, West Virginia
Manat Mustafa, Nazarbayev University, Astana, Kazakhstan
Ronnie Nagloo, University of Illinois-Chicago
Satya Nandakumar, Indian Institute of Technology, Kanpur
Keng Meng (Selwyn) NG, Nanyang Technological University, Singapore
André Nies, University of Auckland, New Zealand
Ludovic Patey, University of Paris Diderot, France
Arno Pauly, Swansea University, Wales
Misha Peretyat'kin, Institute of Mathematics, Almaty, Kazakhstan
Anand Pillay, University of Notre Dame, Indiana
Dilip Raghavan, National University of Singapore
Jan Reimann, Pennsylvania State University, University Park
Christian Rosendal, University of Maryland, College Park
Wim Ruitenburg, Marquette University, Milwaukee, Wisconsin
Luca SAN MAURO, Technical University of Vienna, Austria
Andre Scedrov, University of Pennsylvania, Philadephia
Noah Schweber, Proof School, San Franscisco, California
Paul Shafer, University of Leeds, England
Sasha Shlapentokh, East Carolina University, Greenville, North Carolina
Richard Shore, Cornell University, Ithaca, New York
Steve Simpson, Pennsylvania State University, State College and Vanderbilt University, Nashville, Tennessee
Ted Slaman, University of California-Berkeley
Reed Solomon, University of Connecticut-Storrs
Andrea Sorbi, University of Siena, Italy
Mariya Soskova, University of Wisconsin-Madison
Patrick Speissegger, McMaster University, Hamilton, Ontario, Canada
Frank Stephan, National University of Singapore
Bas Terwijn, Radboud University Nijmegen, The Netherlands
Henry Towsner, University of Pennsylvania, Philadelphia
Todor Tsankov, University of Lyon 1, France
Anush Tserunyan, McGill University, Montreal, Canada
Dan Turetsky, Victoria University of Wellington, New Zealand
Manlio Valenti, University of Wisconsin-Madison
Lou van den Dries, University of Illinois at Champaign-Urbana
Dieter van Melkebeek, University of Wisconsin-Madison
Peter Vranas, University of Wisconsin-Madison
Wei WANG, Sun Yat-sen University, Guangzhou, China
Andreas Weiermann, Ghent University, Belgium
Linda Westrick, Pennsylvania State University
Alex Wilkie, University of Oxford, England
Guohua Wu, Nanyang Technological University, Singapore
Mars Yamaleev, Kazan Federal University
Yue YANG, National University of Singapore
Keita Yokoyama, Tohoku University, Sendai, Japan
Liang YU, Nanjing University, China
Ning ZHONG, University of Cincinnati, Ohio
Boris Zil'ber, University of Oxford, England
Andy Zucker, University of Waterloo, Ontario, Canada

Prepared by Steffen Lempp (@math.wisc.edu">lemppmath.wisc.edu)