Prof. Peter Johnstone | 2 Jul 23:34 2007
Picon
Picon

CT Advisory Committee

Dear fellow-categorists,

On behalf of the international CT Advisory Committee, I am delighted
to announce that Maria Manuel Clementino has agreed to join the
Committee with immediate effect. The current membership of the
Committee, in alphabetical order, is thus as follows:

Maria Manuel Clementino <mmc <at> mat.uc.pt>
Peter Johnstone <ptj <at> dpmms.cam.ac.uk> (Secretary)
Bill Lawvere <wlawvere <at> buffalo.edu> (Chair)
Ross Street <street <at> math.mq.edu.au>
Walter Tholen <tholen <at> pascal.math.yorku.ca>
Myles Tierney <tierney <at> math.uqam.ca>
Richard Wood <rjwood <at> mathstat.dal.ca>

It might be appropriate at this point to remind people of the
Committee's function. It has no official status, and no executive
authority: its sole function is to offer advice, and the benefit
of our collective experience, to those who may
be thinking of organizing international conferences in Category
Theory, with the aim of ensuring that such conferences should take
place on a reasonably regular basis. Anyone who might be thinking
of organizing such a meeting is welcome to contact any member of
the Committee -- but particularly the undersigned -- at any time.

Peter Johnstone

Pedro Resende | 2 Jul 23:58 2007
Picon

New junior research positions in mathematics at IST

I append below an announcement that may be of interest to some
readers of the categories list.
Best,
Pedro.

###########

NEW JUNIOR RESEARCH POSITIONS IN MATHEMATICS AT IST

The Center for Mathematical Analysis, Geometry, and Dynamical Systems
of Instituto Superior Tecnico plans to open soon 4 research positions
in mathematics in one of the areas in which the faculty of the Center
is currently active, privileging the following: differential
equations and dynamical systems (3 maximum); geometry and topology
(including string theory and mathematical-physics) (3 maximum). All
positions are for a period of 5 years, subject to annual evaluations.

The Center is a research and scientific training unit of Instituto
Superior Tecnico (http://www.ist.utl.pt/). It was established in 1991
and develops its activity in mathematics with special emphasis on
nonlinear analysis, dynamical systems, geometry, and topology.

The applicants should hold a Ph.D. in Mathematics or in a related
area relevant to the scientific interests of the faculty of the
Center, for at least 3 years. They must have a strong curriculum and
show a very strong research promise.

Details about these new positions and how to apply will be available
soon in the Center's web page:

(Continue reading)

Michael Barr | 6 Jul 18:55 2007
Picon

Isbell duality

I have seen a reference to Isbell duality.  Can anyone point me to a
definition and any results?

Tom Leinster | 6 Jul 17:50 2007
Picon
Picon

Paper: Euler characteristic as a divergent sum

The following paper is available:

"The Euler characteristic of a category
as the sum of a divergent series"

The Euler characteristic of a cell complex is often thought of as the
alternating sum of the number of cells of each dimension.  When the
complex is infinite, the sum diverges.  Nevertheless, it can sometimes
be evaluated; in particular, this is possible when the complex is the
nerve of a finite category.  This provides an alternative definition of
the Euler characteristic of a category, which is in many cases
equivalent to the original one.

http://arxiv.org/abs/0707.0835

Many thanks to Clemens Berger for suggesting the original idea.

Best wishes,
Tom

Frank de Boer | 9 Jul 16:28 2007
Picon
Picon

Post-doc position in the European project Credo

Postdoc in CREDO project

The position is within the IST-33826 research project CREDO "Modeling and
analysis of evolutionary structures for distributed services". The project
aims at the development and application of an integrated suite of tools
for compositional modeling, testing, and validation of software for
evolving networks of dynamically reconfigurable components.
More information
on this project can be found at http://www.cwi.nl/projects/credo.

The candidate is expected to work on a object-oriented software
development method and architecture to support the
dynamic composition of highly reconfigurable
component-based software systems. The method structures
applications as a network of adaptive concurrent computational tasks that
interact using mobile channels. The research focusses on studying:

(i) the effects of runtime reconfiguration of the network of mobile channels,
and
(ii) the effects runtime changes/upgrades of the computational tasks.

In addition, the applicability of light-weight and automated verification and
model checking techniques and tools will be evaluated in a real-world
case study.

The candidate should have a PhD degree and a background in software engineering,
concurrency and distributed systems, and practical software
development or formal methods.

The postdoc is offered a full-time position for the remaining
(Continue reading)

Reiko Heckel | 10 Jul 00:41 2007
Picon
Picon

Lecturer in Computer Science, University of Leicester

Dear all

the department of CS at Leicester is advertising a lectureship with
focus on software engineering, in particular software evolution and
model transformation, preferably with some formal background in 
algebraic or categorical methods, graph transformation, rewriting, etc.

The deadline for application is July 31, the post is available from
October (and should be filled soon after). Please find further details
below and don't hesitate to contact Jose or myself if you have any
questions.

Best wishes
Reiko

----------------------------------------------------------------------

Lecturer in Computer Science, University of Leicester

Salary Grade 8: £32,976 to £40,335 per annum

Available from 1 October 2007

The University of Leicester seeks to appoint a Lecturer in Computer
Science who can contribute to existing research in model-based software
evolution, including meta-modelling and model transformation,
model-driven development and re-engineering of legacy systems.
Preference will be given to candidates with an interest in formal
techniques who can contribute to and make use of the expertise that the
Department has in algebraic and categorical structures and methods,
(Continue reading)

Steven R. Costenoble | 10 Jul 15:25 2007
Picon

Maps of monads - references

In Toposes, Triples, and Theories, Barr and Wells define a morphism
of triples (which, being a student of Peter May, I will call a map of
monads) in the context of two monads on a given category C. I have a
situation where I have two categories C and D, a monad S on C, a
monad T on D, and a functor F: C -> D. There is a fairly obvious
generalization of the TTT definition, to say that a map from S to T
is a natural transformation FS -> TF making certain diagrams commute.
My guess is that someone else noticed this long ago, so I'm looking
for references to where this has appeared in the literature. I'm
particularly interested in references that include the fact (at
least, I'm pretty sure it's a fact) that such maps are in one-to-one
correspondence with extensions of F to a functor between the
respective Kleisli categories of S and T.

Thanks in advance.

--Steve Costenoble

Steve Vickers | 10 Jul 21:39 2007
Picon
Picon

Re: Maps of monads - references

See Ross Street "The formal theory of monads", JPAA 2 (1972) 149-168
for the general definition, in the abstract setting of a 2-category
instead of Cat.

Actually, there are two obvious generalizations of the TTT definition
("monad functors" and "monad opfunctors"), for the two possible
directions of F.

Steve Vickers.

On 10 Jul 2007, at 14:25, Steven R. Costenoble wrote:

> In Toposes, Triples, and Theories, Barr and Wells define a morphism
> of triples (which, being a student of Peter May, I will call a map of
> monads) in the context of two monads on a given category C. I have a
> situation where I have two categories C and D, a monad S on C, a
> monad T on D, and a functor F: C -> D. There is a fairly obvious
> generalization of the TTT definition, to say that a map from S to T
> is a natural transformation FS -> TF making certain diagrams commute.
> My guess is that someone else noticed this long ago, so I'm looking
> for references to where this has appeared in the literature. I'm
> particularly interested in references that include the fact (at
> least, I'm pretty sure it's a fact) that such maps are in one-to-one
> correspondence with extensions of F to a functor between the
> respective Kleisli categories of S and T.
>
> Thanks in advance.
>
> --Steve Costenoble
>
(Continue reading)

Michael Barr | 10 Jul 23:54 2007
Picon

Re: Maps of monads - references

I think that somewhere Harry Appelgate did something like that, probably
in his Ph.D. thesis.  Whether he ever published it, I cannot now say.

Michael

On Tue, 10 Jul 2007, Steven R. Costenoble wrote:

> In Toposes, Triples, and Theories, Barr and Wells define a morphism
> of triples (which, being a student of Peter May, I will call a map of
> monads) in the context of two monads on a given category C. I have a
> situation where I have two categories C and D, a monad S on C, a
> monad T on D, and a functor F: C -> D. There is a fairly obvious
> generalization of the TTT definition, to say that a map from S to T
> is a natural transformation FS -> TF making certain diagrams commute.
> My guess is that someone else noticed this long ago, so I'm looking
> for references to where this has appeared in the literature. I'm
> particularly interested in references that include the fact (at
> least, I'm pretty sure it's a fact) that such maps are in one-to-one
> correspondence with extensions of F to a functor between the
> respective Kleisli categories of S and T.
>
> Thanks in advance.
>
> --Steve Costenoble
>
>
>

Bill Lawvere | 10 Jul 21:54 2007

CT 07 June 17 - 23, 2007


	The category meeting in Carvoeiro, Portugal held from
June 17th to 23rd, 2007 proved to be one of the most enjoyable
and scientifically promising of the series. This was possible
because of the thoughtful and dedicated organization by
Diana Rodelo, Manuela Sobral, Maria Manuel Clementino, Jorge Picado,
Lourdes Sousa, Gonzalo Gutierres, and Maria Joao Ferreira.
They created a wonderful atmosphere which made possible the
collaboration and friendship between the senior researchers
who were there and the many very intelligent and active young
people, who will be contributing their original research to
future meetings.

	Of course, I was particularly honored by the fact that
the conference banquet took note of my 70th birthday and was
attended by several of my cherished students and colleagues.
I was gratified to meet the many young researchers whom I had not
previously known; they gave me the special gift of hope for the
future of our science.

	My friends and colleagues join me in heartily thanking the
organizers, the scientific committee, and the sponsoring
organizations for having created a most memorable occasion.

	Bill Lawvere

************************************************************
F. William Lawvere, Professor emeritus
Mathematics Department, State University of New York
244 Mathematics Building, Buffalo, N.Y. 14260-2900 USA
(Continue reading)


Gmane