Bob Coecke | 20 Nov 14:49 2014

15 funded PhD positions

... these can be taken up in category theory related areas in the quantum group:

Please contact a potential desired supervisor for more information.


Following a generous donation by Google, the Department of Computer Science at the University of Oxford is
delighted to invite applications for up to 15 fully-funded DPhil (Oxford'ss PhD) studentships tenable
from 1st October 2015.

The University of Oxford is consistently ranked amongst the very best Computer Science departments in the
world, for both teaching and research. We are committed to attracting the world's most talented students
and working with them to continue the success of the department.

The topics for the studentships are open, but should relate to the interests of one of the Department's
research areas: Algorithms, Artificial Intelligence, Automated Verification, Computational
Biology, Foundations, Logic & Structures, Information Systems, Machine Learning, Multi-Agent
Systems, Programming Languages, Security, Semantics and Software Engineering.  We also encourage
applications in cross disciplinary areas such as Linguistics, Biology, Medicine and Quantum
Foundations & Quantum Computation.

The studentships are for three years and are open to students of any nationality.  Each studentship will
cover university and college fees with a stipend of at least £13,863 per year. Applicants are normally
expected to have, or be predicted to achieve, a first-class or a strong upper second-class grade in either
(i) a four-year undergraduate degree (with integrated masters) in a relevant subject (or equivalent
international qualifications), or (ii) a three-year BSc/BA degree followed by excellent
(Continue reading)

Joyal, André | 18 Nov 03:54 2014

RE: Alexandre Grothendieck

Dear Fred,

Grothendieck is gone, what can we say.
He gave us a space where to play.
He was insane some like to say.
This dark world is lasting too long.
Where are light and fire gone?

I am reading a letter of Grothendieck to Thomason (*):

> Ce vent de mépris à l'égard des indispensables travaux de fondements, 
> (et plus généralement, pour tout ce qui ne se conforme pas à la mode du jour).
> ................
> Ce n'était pas une lettre pour "me plaindre" de ceci ou de cela qui me déplaisait.
> Mais c'était une impossible tentative de *partager une douleur*.
> Je savais bien au fond que c'était sans espoir; car tout le monde fuit la douleur, 
> c'est à dire fuit la connaissance (car il n'y a pas de connaissance
> de l'âme qui soit exempte de douleur). 

(*)Lettre sur les dérivateurs (1991).


From: Fred E.J. Linton [fejlinton <at>]
Sent: Monday, November 17, 2014 7:12 PM
To: =?ISO-8859-1?Q?=22Joyal?= <at>; Joyal, André; "categories <at>"
Subject: Re: categories: Alexandre Grothendieck

The best way to describe my reaction to this unwelcome news
(Continue reading)

John Duskin | 17 Nov 17:35 2014

Contact with Grothendieck

My first contact with Grothendieck was in the late sixties through a letter to him from a naive grad student
(me) asking him if I could come to France and study with his group in Paris as I expected a Canadian post doc
which would take me there. In reply, I received a very nice letter from him telling me that I should go to
Strasbourg and study with a new student of his, J.-L.Verdier. That the same sort of thing had sent him to
Nancy rather than Paris when he was young and he had never regretted it. This I did and learned a hell of a lot.

I  got to know him personally quite well after that in Buffalo when he came here  for two summers in 1970-71
thanks to NSF and the department and (his view) that the IHES was funded by the french military. It was a way
that he could fund Survivre. 

Among others, he gave a beautiful series of advanced lectures on the Grothendieck-Teichmuller group  as
well as elementary lectures on sheaf theory. Some of these were recorded and were redone more recently by
Bill Lawvere . Perhaps now these should become available….

John Duskin

[For admin and other information see: ]

Jocelyn Ireson-Paine | 14 Nov 17:24 2014

Category-theory interactive demonstrations on the Web

Dear readers,

here's something I'm pleased with, which I like to advertise every so
often. It's a program running on my Web server which demonstrates category
theory by calculating constructs in the category of sets: .

The page contains instructions, followed by a form which lets you ask the
server to calculate products, equalisers, etc. For example, you can ask it
to calculate the product of sets A and B. You either type in values for
the sets, or let it choose them, and it will calculate the product object
and projection arrows. It will then send back the page, but headed with a
link to your results. These contain a diagram, values for all its objects
and arrows, and an explanation. And, just to make the diagram more vivid,
it rendered in VRML so that you can pick it up and move it about.

To show how general category theory is, I used the same code to calculate
the limit and colimit of simple diagrams representing systems of
interacting objects. You can see a demo of that at .


Jocelyn Ireson-Paine
07768 534 091

[For admin and other information see: ]

(Continue reading)

Moh'd Alsani | 14 Nov 03:50 2014


Very sad news.

Alexander Grothendieck 28 March 1928 – 13 November 2014

[For admin and other information see: ]

Joyal, André | 14 Nov 03:08 2014

Alexandre Grothendieck

Alexandre Grothendieck died this morning November 13

----- Message transféré de jean.malgoire <at> -----
   Date: Thu, 13 Nov 2014 23:00:54 +0100
     De: jean.malgoire <at>
Objet: décès d'Alexandre Grothendieck
      À: all-user <all-users <at>>

Je viens d'être informé du décès d'Alexandre Grothendieck ce matin 13
novembre à l'hopital de Saint-Girons en Ariège.

jean malgoire

----- Fin du message transféré -----

[For admin and other information see: ]

Paoli, Simona (Dr. | 13 Nov 17:01 2014

First YaMCATS meeting: December 18, Leicester (UK)

*** First Yorkshire and Midlands Category Theory Seminar
*** December 18th, 2014
*** Department of Mathematics, University of Leicester (UK)

We are pleased to announce the formation of a new research network in categ=
ory theory between the Universities of Leeds, Leicester and Sheffield. The =
network is called YaMCATS (Yorkshire and Midlands Category Seminar) and is =
partially funded by the London Mathematical Society.
The first YaMCATS meeting will take place at the University of Leicester on=
  Thursday 18 December. The speakers are:
Peter Johnstone (University of Cambridge)
Dorette Pronk (Dalhousie University)
Daniel Shaeppi (University of Sheffield)
Further details of the programme will be posted in due course on the YaMCAT=
S website:
The meetings are open to all and everybody is welcome.=20
If you have any questions about YaMCATS, please do not hesitate to contact =
Best regards,
The YaMCATS organizers ,
(Continue reading)

Garraway, Dale | 12 Nov 19:46 2014

Request for a reference

Hi All

Could some one please send me a reference of the fact that the category of
presheaves on a Heyting algebra $H$ is equivalent to the category of
sheaves on the Heyting algebra of down closed subsets of $H$.  I believe
this is true in general for any partial order so a reference to either
would be greatly appreciated.

Dale Garraway
Dept. of Math, 
Eastern Washington
dgarraway <at>

[For admin and other information see: ]

Tom Leinster | 10 Nov 20:49 2014

Research fellowship at Edinburgh

Dear all,

We have a two-year postdoc available at Edinburgh:

It's open across the mathematical sciences, so competition will be stiff!

Edinburgh is a good place for a category theorist to be.  Feel free to
contact me if you have questions.

Best wishes,


The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

[For admin and other information see: ]

David Roberts | 10 Nov 02:42 2014

NNOs in different toposes "the same"?

Hi all,

If have a geometric morphism f: E -> F, what's the/a sensible way to
say that the natural number objects of E and F are 'the same'? If f is
local, then f_* preserves colimits, and so both f^* and f_* respect
natural numbers objects up to iso. But this is a little too strong,
perhaps, since we only need f_* to respect finite limits to use the
characterisation of |N by Freyd to show preservation. What other
conditions could I impose, other than simply that f_* preserves the

Secondly, what if E is the externalisation of an internal topos in F?
For instance, F = Set and E the externalisation of a small topos, not
necessarily an internal universe (in fact I don't want this to be the
case!). Then if I can say what it means for the NNO in E to be 'the
same as' that in F, I can say that the internal topos has the same NNO
as the ambient category.




Dr David Roberts
Research Associate
School of Mathematical Sciences
University of Adelaide
SA 5005

(Continue reading)

David Roberts | 6 Nov 02:51 2014

Journal of K-Theory effectively defunct

Some people may be affected by this, so I share it here.

The editorial board of JKT has resigned (almost) en masse in protest
of the continuing private ownership of the journal. They have started
a new journal owned completely by the non-profit K-Theory Foundation.

Details are in the open letter



[For admin and other information see: ]