The 93rd PSSL took place in Cambridge, UK on the weekend of 14/15 April 2012. Talks were held at the Centre for Mathematical Sciences. The conference started at 9am on the Saturday and finished sometime during the afternoon of the Sunday. There are now pictures of the event taken by J├╝rgen Koslowski, and also the group picture.

What is a PSSL?

The PSSLs are a long-running series of meetings, usually held over a weekend at a university in Europe. Talks cover all aspects of category theory and its applications. The working atmosphere is informal, e.g. talks are usually short and may be about work in progress. The name is a (charming) historical relic - 'Peripatetic Seminar on Sheaves and Logic' - but most talks are not about sheaves or logic.
Attendance is free, and everyone is invited to offer a talk.

Last Details

There is a map with the main locations here.


Most people stayed at Fitzwilliam College. Semi-ensuite rooms have a wash basin and shower and cost £49 per night. Full ensuite rooms cost £67 per night.


Abstracts can be found here. Slides of some talks are available below.

8:30 onwards: Registration
9:00 Announcements
9:15 Eugenia Cheng: Multivariable adjunctions and mates
9:45 Nick Gurski: The Gray tensor product via factorization
10:15 Igor Bakovic: Fibrations in tricategories
10:45 Coffee Break
11:15 Dion Coumans: Generalizing canonical extension to the categorical setting
11:45 Paul Taylor: Semilattice bases for Locally Compact Spaces
12:15 Benno van den Berg: Predicative toposes revisited
12:45 Lunch
14:00 Tom Leinster: The eventual image
14:30 Michael Shulman: Euler characteristics of colimits
Chris Heunen: Relative Frobenius algebras are groupoids
15:30 Coffee Break
16:00 Finn Lawler: Biprofunctors and proarrow equipments
16:30 Marie Bjerrum: The closure of a class of finite limits by mixed interchange in Set
17:00 End of talks
18:00 Drinks in Queens' College President's Lodge until 18:45
19:00 Dinner in Pizza Express, Jesus Lane

9:00 Marek Zawadowski: The Theories of Analytic Monads
9:30 Mike Stay: Compact closed bicategories
10:00 Jamie Vicary: A 2-Categorical Formalism for Quantum Information
10:30 Coffee Break
11:00 Marino Gran: Weighted commutators in semi-abelian categories
11:30 Tim Van der Linden: The commutator Condition for higher central extensions
12:00 Nelson Martins-Ferreira: Topological space objects
12:30 Lunch
14:00 Jiri Rosicky: Rigidification of algebras over essentially algebraic theories
14:30 John Bourke: 2-dimensional monadicity
15:00 Daniela Petrisan: Relation lifting, with an application to the many-valued cover modality
15:30 Jürgen Koslowski: A categorical approach to generating online machine models for formal languages from grammars
16:00 Finish (possibly coffee)

List of participants

Danel Ahman, University of Cambridge
Thomas Athorne, University of Sheffield
Octavian Babus, University of Leicester
Igor Bakovic, Institut des Hautes Études Scientifiques
Filip Bár, University of Cambridge
Marie Bjerrum, University of Cambridge and Paris 13
John Bourke, Masaryk University, Brno
Liang-Ting Chen, University of Birmingham
Eugenia Cheng, University of Sheffield
Maria Manuel Clementino, Universidade de Coimbra
Thomas Cottrell, University of Sheffield
Dion Coumans, Radboud University Nijmegen
Bao Long Dang Van, Université catholique de Louvain
Nadish de Silva, University of Oxford
Barry Devlin, University of Glasgow
Andreas Döring, University of Oxford
Mathieu Duckerts-Antoine, Université catholique de Louvain
Jonathan Elliott, University of Sheffield
Tomas Everaert, Vrije Universiteit Brussel
Hiro Funakoshi, University of Cambridge
Julia Goedecke, University of Cambridge
Marino Gran, Université catholique de Louvain
Nick Gurski, University of Sheffield
Chris Heunen, University of Oxford
Martin Hyland, University of Cambridge
Peter Johnstone, University of Cambridge
Rudger Kieboom, Vrije Universiteit Brussel
Jürgen Koslowski, Technische Universität Braunschweig
Achilleas Kryftis, University of Cambridge
Klaas Landsman, Radboud Universiteit Nijmegen
Finn Lawler, Trinity College, Dublin
Sori Lee, University of Cambridge
Tom Leinster, University of Glasgow
Paul Levy, University of Birmingham
Guilherme Lima, University of Cambridge
Francisco Lobo, University of Manchester
Ignacio López Franco, University of Cambridge
Fosco Loregian, Padua University
Zhen Lin Low, University of Cambridge
Daniel Marsden, University of Oxford
Nelson Martins-Ferreira, Instituto Politécnico de Leiria, Portugal
Yoshihiro Maruyama, University of Oxford
Rasmus Mogelberg, IT University of Copenhagen
Daniela Petrisan, University of Leicester
Andrew Pitts, University of Cambridge
Oriol Raventós, Masaryk University, Brno
Diana Rodelo, Universidade do Algarve
Jiri Rosicky, Masaryk University, Brno
Giuseppe Rosolini, DIMA, Università di Genova
Michael Shulman, University of California
Harold Simmons, University of Manchester
Sam Staton, University of Cambridge
Mike Stay, University of Auckland and Google
Richard Steiner, University of Glasgow
Wouter Stekelenburg, Utrecht University
Herman Stel, Università degli studi di Firenze
Isar Stubbe, Université du Littoral-Côte d'Opale, Calais
Paul Taylor
Christopher Townsend
Henning Urbat, Technische Universität Braunschweig
Christina Vasilakopoulou, University of Cambridge
Matthijs Vákár, University of Cambridge
Benno van den Berg, Universiteit Utrecht
Tim Van der Linden, Université catholique de Louvain
Jaap van Oosten, Universiteit Utrecht
Jamie Vicary, National University of Singapore and University of Oxford
Tamara von Glehn, University of Cambridge
Marek Zawadowski, University of Warsaw

Conference dinner

There was a conference dinner on the Saturday evening at 19:00, at Pizza Express.
There was also a (free!) reception at Queens' College in the President's Lodge, to which we were kindly invited by the President Lord Eatwell. This was from 18:00 to 18:45 on the Saturday..


The most convenient airport for getting to Cambridge is Stansted. From there you can get either a train or a bus to Cambridge. Another possibility is of course the Eurostar to London St Pancras, and then a train from London Kings Cross to Cambridge. If you would like any more advice on travel, don't hesitate to contact the organiser.