101st Peripatetic Seminar on Sheaves and Logic

September 16th-17th, 2017

University of Leeds

Picture of University of


  • PSSL 101. The 101st Peripatetic Seminar on Sheaves and Logic (PSSL 101) will be held on the weekend of Saturday 16th and Sunday 17th 2017 at the School of Mathematics, University of Leeds. Following the tradition of the PSSL, this is intended to be an informal meeting, covering all areas of category theory and its applications. Talks by PhD students and young researchers are particularly encouraged. For a history of the PSSL, please see here.
  • Pre-PSSL lectures. There will be two lectures in the afternoon of Friday 15th September (14:30-15:30 and 16:00-17:00) to be given by Jiri Rosicky and Andrew Brooke-Taylor, on connections between locally presentable categories, set theory, and model theory. 

Travel and directions

  • By plane: you can fly to either Leeds-Bradford Airport (LBA) or Manchester Airport (MAN).
    • From Leeds Bradford Airport, you can either take a taxi or bus line 757, which leaves in front of the airport and goes to Leeds Train Station.
    • From Manchester Airport, there are frequent trains from Manchester Airport to Leeds Train Station (either direct or via Manchester Piccadilly). The journey takes approximatively 75 minutes.
  • By train: you can travel to Leeds Train Station (LDS). Please consult National Rail Enquiries Website and Transpennine Express for details. 
  • By car: please see the instructions here. If you wish to park on campus, it is necessary to contact us well in advance, since all parking must be pre-booked by a member of staff. 

The following information can be useful to arrive at the University of Leeds once arrived in Leeds:

  • Directions to the University of Leeds can be dowloaded from this link.
  • Walking directions from Leeds Train Station can be found here.
  • A campus map can be downloaded from this link.
  • Lectures will be held in the School of Mathematics of the University of Leeds in the MALL room on Level 8. 


There are various hotels nearby where you can book accommodation on your own, e.g.:

Cheaper alternatives include the following:

Registration and submission of talks

  • There is no registration fee. To register and submit a talk, please download the form below:

Registration Form

and return it by email to n.gambino AT leeds.ac.uk by Friday 1st September 2017

Equivalence statue


Click on a title to see the abstract of the talk, or see this page for the complete list.

Friday 15th September (pre-PSSL lectures)

School of Mathematics, MALL (Level 8)

Rosický - Internal sizes in accessible categories
Coffee break
Brooke-Taylor - Powerful Images for Abstract Elementary Classes

Saturday 16th September

School of Mathematics, MALL (
Level 8)

Johnstone - Anti-Boolean toposes and infinitesimal generation
Faber - Toposes of  finitely supported M-Sets
Hazratpour - Fibrations of toposes
Coffee break
Rosický - Barely locally presentable categories
Espindola - Stone duality for infinitary first-order logic
Di Liberti - Weak saturation and weak amalgamation property
12:30-14:00 Lunch break
Adámek - Codensity monads and density comonads of set functors
Ghiorzi - Internal enriched categories
15:00-15:30 Taylor - Bimonoidal adjunctions
15:30-16:00 Coffee break
16:00-16:30 Koslowski - Augmenting graphs with memory: categorical models for (2)PDAs and generalised context-free grammars
16:30-17:00 Hines - A diagrammatic calculus for cryptographic protocols
17:00-17:30 Townsend - Hilsum-Skandalis maps in a cartesian category

Sunday 17th September

School of Mathematics, MALL (
Level 8)

Verity - TBA
Corner - Fubini for codescent objects
Verdon - Coherence for symmetric and braided pseudomonoids
Coffee break
Goedecke - Hopf formulae for Tor
11:30-12:00 Charamboulous - On Galois and Tannakian categories
12:00-12:30 Patta - A categorical perspective on Entropy and a categorification of topological semimodules
Lunch break
Bourke - Equipping weak equivalences with algebraic structure
Swan - Lifting problems in a Grothendieck fibration
Blechschmidt - Using the internal language of toposes in commutative algebra
Coffee break
Kraus - (n,1)-categories in univalent type theory
16:30-17:00 Weinberger - Interpreting type theory in appropriate presheaf toposes
van den Berg - Univalent polymorphism

Abstracts of talks

See here.


  1. Jiří Adámek (Braunschweig)
  2. Ingo Blechschmidt (Augsburg)
  3. Benno van den Berg (Amsterdam)
  4. Andrew Brooke-Taylor (Leeds)
  5. John Bourke (Macquarie)
  6. Nigel Burke (Cambridge)
  7. Paolo Capriotti (Nottingham)
  8. Gianpietro Colato (Louvain)
  9. Georgios Charalambous (Cambridge)
  10. Alex Corner (Sheffield Hallam)
  11. Ivan Di Liberti (Masaryk)
  12. Christian Espindola
  13. Eric Faber (Cambridge)
  14. Yuning Feng (Birmingham)
  15. Cesare Gallozzi (Leeds)
  16. Nicola Gambino (Leeds)
  17. Enrico Ghiorzi (Cambridge)
  18. Julia Goedecke (Leicester)
  19. Marino Gran (Louvain)
  20. Sina Hazratpour (Birmingham)
  21. Peter Hines (York)
  22. Martin Hyland (Cambridge)
  23. Peter Johnstone (Cambridge)
  24. Jürgen Koslowski (Braunschweig)
  25. Nicolai Kraus (Nottingham)
  26. Marco Larrea-Schiavon (Leeds)
  27. Richard Matthews (Leeds)
  28. Adrian Mathias (Leeds)
  29. Jiri Rosicky (Brno)
  30. Sean Moss (Cambridge)
  31. Simona Paoli (Leicester)
  32. Vaia Patta (Oxford)
  33. Gun Pinyo (Nottingham)
  34. Jiří Rosický (Masaryk)
  35. Andrew Smith (Leicester)
  36. Raffael Stenzel (Leeds)
  37. Andrew Swan (Amsterdam)
  38. Paul Taylor (Birmingham)
  39. Christopher Townsend
  40. Joost van Dijk (Amsterdam)
  41. Dominic Verdon (Oxford)
  42. Dominic Verity (Macquarie)
  43. Jakob Vidmar (Leeds)
  44. Jonathan Weinberger (Darmstadt)

Organizing committee

  • Andrew Brooke-Taylor (Leeds)
  • Nicola Gambino (Leeds)
  • Peter Johnstone (Cambridge)

This page was last modified on September 2nd, 2017 by Nicola Gambino