Peripatetic Seminar on Sheaves and Logic

[it's now 2020, instead of 2017 and because of the zulip for category theory guys were asking https://categorytheory.zulipchat.com/# I decided to try to complete this list, at least a bit.  I will produce the spreadsheet required, with  links later on. for the time being just adding Peter Johnstone compilation of the list until the 100th PSSL (Many thanks to Julia Goedecke for that!) and the few recent ones I could find easily online.

From the comments (by myself)
Probably should do something clever like a spreadsheet or something, but
PSSL 95, 26th and 27th of April 2014 Brno, Czech Republic, http://math.muni.cz/~bourkej/PSSL95. 

The Seminaire Itinerant des Categories, 17 mai 2014, http://sites.uclouvain.be/bcts/sic2014/. 

Lastly Peripatetic Seminar on Sheaves and Logic PSSL 96. October 11-12, 2014, University of Palermo, Italy. http://math.unipa.it/metere/PSSL96/

so ok, we got the websites for PSSL 105 https://sites.google.com/view/pssl-105.
 and PSSL 104 https://mysite.science.uottawa.ca/phofstra/PSSL18.html. 

 Looks like we're out of luck with PSSL 103. Google only found "Masaryk University will host the 103rd edition of PSSL. We look forward to see you in Brno! all the relevant informations are on the conference website." but he conference website gives me a 404. 

I had more luck with PSSL 102, https://www.usc.es/regaca/pssl102/ 

Finally we get http://www1.maths.leeds.ac.uk/~pmtng/PSSL/pssl101.html.]


I've been trying to find the records of the Peripatetic Seminar on Sheaves in Logic. Gavin Wraith provided a very nice collection with all the the titles and speakers from  1976 till 1999 (PSSL 70). What  has happened since?

The categories mailing list  conference page seems to have most (missing only PSSL81?) of the announcements of  PSSLs. Maybe this list should be in the opposite order to facilitate additions, but here it goes.

Peripatetic Seminar on Sheaves and Logic PSSL 71 The 71st meeting of the PSSL was held in Louvain-la-Neuve on the weekend of 16-17 October 1999.PeripateticSeminar on Sheaves and Logic 71 (I couldn't find the webpage.)

Category Theory Symposium (PSSL 72) A "PSSL-like" meeting on category theory was held in Brussels, April 8-9. Please check out the webpage http://www.vub.ac.be/CLEA/BobWS2000.html  
Bob Coecke's old webpage has the program for PSSL72.

Peripatetic Seminar on Sheaves and Logic PSSL 73 The 73rd meeting of the seminar was held at the Department of Theoretical Computer Science of the Technical University in Braunschweig, Germany, over the weekend of April 29-30, 2000. Contact: Jurgen Koslowski, koslowj@iti.cs.tu-bs.de , the program is in Jurgen's webpage.

The 74th PSSL was held in Cambridge on the weekend of 4/5 November 2000. Also an opportunity for anyone who hasn't been in Cambridge recently to see the new Mathematics building.

Peripatetic Seminar on Sheaves and Logic (PSSL 75) The 75th meeting of the Peripatetic Seminar on Sheaves and Logic was held at the Institut Mittag-Leffler, Stockholm, on the week-end of 9-10 June 2001. The meeting may be seen as a satelitte event of the Logic Year, which is taking place at the Mittag-Leffler Institute in the context of the Logic Year.
Anders Kock, Erik Palmgren, Dana Scott 
The 75th PSSL webpage is here.


Peripatetic Seminar on Sheaves and Logic PSSL 76 The 76th meeting of the Peripatetic Seminar on Sheaves and Logic was held at the IT-University of Copenhagen over the weekend 2-3 March, 2002. For information: www.it-c.dk/research/theory/Seminars/pssl76.html 

Peripatetic Seminar on Sheaves and Logic PSSL 77 The 77th meeting of the seminar was held at the Department of Theoretical Computer Science of the Technical University in Braunschweig, Germany, over the weekend of October 5/6, 2002. For information: http://www.iti.cs.tu-bs.de/TI-INFO/koslowj/PSSL77.html

Peripatetic Seminar on Sheaves and Logic PSSL 78 The 78th meeting of the PSSL was held in Strasbourg over the weekend of 15-16 February 2003. Contact:
crans@math.u-strasbg.fr 

Peripatetic Seminar on Sheaves and Logic PSSL 79 A PSSL was organized by the University of Utrecht on the weekend of the 28th and 29th of June, 2003.

Peripatetic Seminar on Sheaves and Logic PSSL 80 A PSSL was held on the weekend of 3rd and 4th April, 2004 in Cambridge, UK, organized by Eugenia Cheng. The program is  in http://cheng.staff.shef.ac.uk/pssl80/

Peripatetic Seminar on Sheaves and Logic PSSL 81
was held in the  Department of Mathematics, University of Coimbra, PORTUGAL in 9-10 April, 2005. More information, including the program can be found at http://www.mat.uc.pt/~categ/events/pssl.html.


International Conference "Charles Ehresmann 100 ans" October 7 to 9, 2005, at the Universite de Picardie Jules Verne in Amiens.
Including the 82nd session of the PSSL "Peripatetic Seminar on Sheaves and Logic" and a session of the SIC (Seminaire Itinerant de Categories). See
http://perso.wanadoo.fr/vbm-ehr/ChEh

Peripatetic Seminar on Sheaves and Logic PSSL 83 A PSSL was held at Glasgow, Scotland, on 6-7 May, 2006. For information, see
http://www.maths.gla.ac.uk/~tl/pssl/ 

Peripatetic Seminar on Sheaves and Logic PSSL 84 A PSSL was held on the weekend of 14th and 15th October at the Department of Theoretical Computer Science of the Technical University in Braunschweig, Germany.  See  http://www.iti.cs.tu-bs.de/TI-INFO/koslowj/PSSL84.html 

Peripatetic Seminar on Sheaves and Logic PSSL 85. A PSSL was held on the weekend of 24th and 25th March, 2007 in Nice, organized by Eugenia Cheng, the schedule is http://cheng.staff.shef.ac.uk/pssl85/index.html#schedule.

Peripatetic Seminar on Sheaves and Logic PSSL 86. 8th and 9th September, 2007. Institut Élie Cartan of the Université Henri Poincaré in Nancy. Organizer: Francois Lamarche.
http://www.loria.fr/~lamarche/psslHomeEN.html 

Peripatetic Seminar on Sheaves and Logic PSSL 87. Honouring A. Kock, on the occasion of his 70th birthday, 22-23 March 2008. An extra session of invited talks on Friday 21 March with A. Joyal, F.W. Lawvere and G. Reyes. Organizer: Panagis Karazeris. See the web page:
http://www.math.upatras.gr/~pssl87 

Peripatetic Seminar on Sheaves and Logic PSSL 88. Honouring Martin Hyland and Peter Johnstone on the occasion of their 60th birthdays, 4th-5th April 2009. See the web page:
http://cheng.staff.shef.ac.uk/pssl88/ 

Peripatetic Seminar on Sheaves and Logic PSSL 89. 12th-13th December 2009 in Louvain-la-Neuve, Belgium. Information is available at http://homepages.vub.ac.be/~tvdlinde/pssl89.html 

Peripatetic Seminar on Sheaves and Logic PSSL 90. April 24-25, 2010 at the Department of Theoretical Computer Science of the Technical University Braunschweig, Germany. Information is available at http://www.iti.cs.tu-bs.de/TI-INFO/koslowj/PSSL90.html 

Peripatetic Seminar on Sheaves and Logic PSSL 91. November 27-28, 2010, Amsterdam. Information is available at http://staff.science.uva.nl/~ciancia/PSSL91/ 

Peripatetic Seminar on Sheaves and Logic PSSL 92. April 23-24, 2011, Oxford, UK.

Peripatetic Seminar on Sheaves and Logic PSSL 93. April 14-15, 2012, Cambridge, UK. See https://www.dpmms.cam.ac.uk/~jg352/PSSL93.html 

Peripatetic Seminar on Sheaves and Logic PSSL 94, 25-28 March, 2013, University of Sheffield, an event Eugenia Cheng  co-organised with David Jordan. The program is at http://cheng.staff.shef.ac.uk/pssl94/


By the way the picture is the Milky Way in Bear Valley, courtesy of Christian Le Cocq.

Ada Lovelace Day 2013...

So it seems that this was the fourth year that the interwebs celebrated Ada Lovelace's Day. I think this is a good thing and like to join in the celebrations...

Previous years I have posted about Karen Sparck-Jones and Christine Ladd-Franklin.
This year there was a suggestion of going and adding some more women scientists to Wikipedia and I'm planning to do so, as soon as I have a few spare minutes. Soon, very soon.

I  have also  tried to help  Catarina Dutilh Novaes and friends put online a directory of Women in Logic. (Anna Crouch did the boring job of finding the websites of the women already in the list, thanks Anna!)

Go on, friends, add yourselves in!

But meanwhile this year I think I've decided that it's best to celebrate the people that work in my favorite kind of mathematics, Category Theory. So here is Marta Bunge, looking very serious,  in a picture taken by Andrej Bauer.

Geoglyphs: Amazonian civilization?...

This is not the link I was looking for, but goes in the same direction, in 2003, from NBC

Similarly this from National Geographic in 2008. and the Washington Post in  September 2010.

The Discovery magazine  in January 2010 consults a Brazilian in Para', and links to its other story and the Guardian one.

 Michael Heckenberger is one name that turns up many times. and Denise Schaan too, need to check these guys.

Asking KB Questions

The print here is by Tatsuo Horiuchi, who uses Excel to draw beautiful Japanese pictures. This is strangely apt as a caption for a post on question answering, actually.

Some times bits of information get stuck in your head and keep coming back when you're having a shower or driving, pestering you for no good reason...

Right now the bit of information that is annoying me like food-stuck-between-your-teeth is the Standard Model of Question Answering using  knowledge bases or KBs. Say you have a question Q, a proposed answer A for the question and a knowledge base KB that is supposed to help you answer the question.

It is usual to say that A is a good answer for Q, provided by the knowledge base KB, which we could write as  Answers(A, Q, KB)  if the declarative form of the question Q matches the assertion A and A is entailed by the contents of the  KB.

A simple example of question Q is "What is the capital of France?" The declarative version of this question could be written as  capital(France, ?) where I am writing ? for the thing I don't know. So if the KB has a triple "capital(France, Paris)", then  the KB entails a good answer for Q, or KB |- A and  A is a good answer for Q, using the traditional symbol of entailment so loved by logicians.

Thus in the standard model we have to do two things:
1. we need to show that KB entails A (proof theory in databases? how long can the proof be?)  and
2. we need to show that A matches (how closely?) the declarative form of the question Q.

There are plenty of deficiencies of this standard model: 
1. Sometimes answers do not directly match the  form of the question, but imply it in conjunction with additional (background) knowledge, you could call it More-Informative answers. For example, if the question was:

        Q: Is Paris in France?
        A: Paris is the capital of France (Since being the 'capital of' a country implies being 'in the country', this  is a more informative answer than the question you asked. You have to do some inference to obtain the answer really asked for.)
2. Sometimes you'd prefer to see Qualified answers
        Q: How much for "The Dark Knight"?
        A: To see it now, you have to pay $13.95 On Demand, Netflix announced it will have for free next week.
Another example:
        Q: What is the dosage of aspirin for fever?
        A: For infants 100 mg, for children 200 mg, for adults 300 mg...
3. Sometimes more than qualified answers, you want Ranked Answers
         Q: How do I get to Boston?
         A: There are multiple flights or train or bus itineraries, depending on who you are, where you are, how much money you want to spend, etc..
       Multiple correct answers but of varying relevance...

Given that we do want these kinds of answers, which are more informative, Dick Crouch describes an improved model of KB-based question  answering. Say A answers question Q using KB and a collection of backgroung assumptions B plus a set of extra suppositions S if

Answers(A, Q, KB, B, S)   if:

1. KB |-  A the answer A 'follows from'  the KB;
2. the declarative form of the question Q follows from some background knowledge B, some extra suppositions S and the answer A,   A&B&S |- Q^d
3. the background knowledge follows from the KB, KB |- B (are these the same kinds of proofs as before?)
4. the additional suppositions do not follow from the KB, KB |-/- S
5. the additional suppositions do not entail the declarative form of the question S|-/- Q^d

But I wonder how S and B come about and from where.
It looks like  B ought to be part of a common stock of general knowledge that my KB should have or would have if it knew about Common Sense, while S consists of extra assumptions that no amount of generic knowledge about the world would provide. Does this make sense?

IMLA 2011: Nancy, France

Natasha Alechina and I decided that it was time to make an IMLA that appealed to the philosophical logicians amongst us. So we proposed a workshop associated to the  14th Congress of Logic, Methodology and Philosophy of Science LMPS in Nancy, France.

The program is below. This gave origin to a special issue of the IGPL that we are still trying to finish...

Programme:

8:30-8:45 - introduction Valeria and Natasha
8:45-9:30 INVITED SPEAKER: Michael Mendler
9:30-10:00 contributed paper Robert Simmons/Bernardo Toninho
10:00-10:30 COFFEE BREAK
10:30-11:15 INVITED SPEAKER: Luiz Carlos Pereira
11:15-12:00 INVITED SPEAKER: Brian Logan
12:00-12:30 contributed paper: Gianluigi Bellin
12:30 - 2:15 LUNCH BREAK
2:15 - 3:00 INVITED SPEAKER: Lutz Strassburger
3:00-3:30 contributed paper: Newton M. Peron and Marcelo E. Coniglio
3:30-4:00 contributed paper: Giuseppe Primiero
4:00-4:14  closing remarks Valeria and Natasha

IMLA 2008: Pittsburgh

Sadly this LICS was the last time I saw John Reynolds, a very nice person as well as a great fore founder of our discipline.

Here's the very colourful program of IMLA, reproduced in B&W below:

MONDAY JUNE 23 IMLA Workshop Steinberg Auditorium, Baker Hall A53
8:30-9:30 Registration
10:00-10:45 Invited Talk: Frank Pfenning
10:45-11:00 Break
11:00-11:30 Kensuke Kojima, Atsushi Igarashi:
On Constructive Linear-Time Logic
11:30-12:00 Rene Vestergaard, Pierre Lescanne, Hiroakira Ono: Constructive rationality implies backward induction for conscientious players
12:00-12:30 Simon Kramer: Reducing Provability to Knowledge in Multi-Agent Systems
12:30-2:00 Lunch
2:00-3:00 Invited Talk: Torben Brauner
3:00-3:30 Neelakantan Krishnaswami: A Modal Sequent Calculus for Propositional Separation Logic
3:30-4:00 Break
4:00-4:30 Didier Galmiche, Yakoub Salhi: Calculi for an Intuitionistic Hybrid Modal Logic
4:30-5:00 Kurt Ranalter: Two-sequent K and simple fibrations
5:00-5:30 Deepak Garg: Principal-centric Reasoning in Constructive Authorization Logic

IMLA 2005: Chicago

The Chicago version of IMLA was organized by  Frank Pfenning and myself. It was (or  perhaps, it felt) more computationally oriented than the previous two, possibly because of Frank Pfenning's influence. Here's the webpage for the workshop.

It was  very hot  in Chicago in June, 30th, 2005.

Preliminary Program:

All talks will be in the School of CTI, DePaul University, 243 South Wabash Ave. The room is TBA.
9:40		Opening Frank Pfenning, Carnegie Mellon University
9:45		INVITED TALK: Checking Properties of Pointer Programs David Walker, Princeton University
10:30		Coffee Break
11:00		A Modal Calculus for Named Control Effects Aleksandar Nanevski, Carnegie Mellon University
11:30		A Computational Interpretation of Classical S4 Modal Logic Chun-chieh Shan, Harvard University
12:00		A Term Calculus for Dual Intuitionistic Logic Gianluigi Bellin, University of Verona & QMW College, University of London
12:30		Lunch
14:00		INVITED TALK: Intuitionistic Modal Logic: observations from algebra and duality Yde Venema, University of Amsterdam
14:45		Labeling Sequents: motivations and applications Patrick Girard, Stanford University
15:15		On the inferential role semantics of modal logic Charles Stewart, Dresden University of Technology
15:30		Coffee Break
16:00		SPECIAL CONTRIBUTION: Gödel's Interpretation of Intuitionism William W. Tait, University of Chicago
16:45		Constructive Description Logics: work in progress Valeria de Paiva, PARC
17:00		End