Jeremy Gibbons | 22 Nov 13:02 2015

SIGPLAN John C Reynolds Doctoral Dissertation Award

Dear All,

I would like to draw your attention to the SIGPLAN John C. Reynolds Doctoral Dissertation Award. If you are
(or will be) a 2015 PhD graduate with a great thesis or a supervisor of such a graduate can I suggest you
consider applying? Obtaining such an award makes a person stand out when applying for positions. 

The nomination process is straightforward and nominations are due on the 5th of January. Details of the
award can be found at . If you have any questions, please
contact Susan Eisenbach (CC'd).


Jeremy.Gibbons <at>
Oxford University Department of Computer Science,
Wolfson Building, Parks Road, Oxford OX1 3QD, UK.
+44 1865 283521

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John Baez | 22 Nov 01:56 2015

Unexampled richness

Dear Categorists -

pjf wrote:

Jim Holt wrote in his "Diary" on Slate, 2000--11--27
>    Category theory is a ridiculously abstract framework that takes all
>    the meaning out of mathematics.
> In his review of Michael Harris's "Mathematics Without Apologies:
> Portrait of a Problematic Vocation" (Princeton University Press, 2015)
> Holt writes (The New York Review of Books, 2015--12--03):
>     ...Grothendieck made [category theory] sing. Between 1958 and 1970,
>    he used category theory to create novel structures of unexampled
>    richness.

Given the first quote, I wonder if Holt is making a subtle dig at
Grothendieck here, hinting that he doesn't consider enough examples!

I suppose you all know this joke:

One striking characteristic of Grothendieck’s mode of thinking is that it
> seemed to rely so little on examples. This can be seen in the legend of the
> so-called “Grothendieck prime”. In a mathematical conversation, someone
> suggested to Grothendieck that they should consider a particular prime
> number. “You mean an actual number?” Grothendieck asked. The other person
> replied, yes, an actual prime number. Grothendieck suggested, “All right,
> take 57.”
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Michael Barr | 18 Nov 23:18 2015

Springer violates copyright!

As most of you know, Charles Wells and I published Toposes, Triples, and 
Theories in 1984.  Several years later, the book was sold out and, in 
accordance, I believe, with the 1980 copyright law, they had to reprint or 
return the copyright to the authors.  They chose the latter option.  They 
sent us letters saying that we were now the owners of the copyright. 
Unfortunately, neither of us has saved the letter.  Nonetheless they did 
return the copyright.

Browsing their web site a couple months ago, I noticed that they are 
selling the book again, just as though they still own the copyright. 
They are selling an electronic version, as well as what they describe as a 
paperback version, which is almost surely print-on-demand.  I haven't 
looked (I would have to pay to) but I assume that what they are selling is 
a scan of the inferior printed version.  (It is inferior owing to the use 
of a poor quality printer.)  Needless to say that have not offered either 
of us any royalties.  They have also ignored a complaint I wrote them.

Most of you probably know that a slightly revised and corrected version is 
available free as TAC reprint #12 as well as on both Charles's and my web 
sites.  And any copy shop will print and bind you a copy more cheaply than 


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Vladimir Voevodsky | 18 Nov 14:51 2015

a question


could anyone point me out to a proof that the category F whose objects are natural numbers and morphisms are
morphisms of finite sets is a free category with coproducts where the associativity and unity
isomorphisms are identities generated by one object?

Thank you in advance,

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Oosten, J. van | 18 Nov 13:47 2015

98th PSSL -- first announcement

Dear all,

We are happy to announce the 98th Peripatetic Seminar on Sheaves and
Logic, which will
take place during the weekend of 8-10 January 2016. As usual, we invite
talks on every
aspect of category theory or its applications in mathematics.

We have booked a conference centre in a wooded area near the University
of Utrecht,
which offers full board and lodging and lecture room facilities. We can
use some grant
money so that the local expenses for the participants will be kept to a
minimum. The web site
of the centre is (but precise travel
instructions will be given
in a further announcement).

However, we could only make this arrangement for a maximum of 40
participants. We
therefore ask participants to register NO LATER than December 17, by an
e-mail sent to
Benno van den Berg: bennovdberg <at> Registration will be dealt
with on a first
come first serve basis.

We look forward to seeing you in the new year!

Benno van den Berg
Ieke Moerdijk
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pjf | 15 Nov 03:23 2015

2 is an unexampled even prime

I wrote that I didn't know what "unexampled richness" means. Fred
Linton was the first to tell me that it means unparalleled. Indeed,
the Oxford English Dictionary gives the definition:

    Having no preceding or similar example; unprecedented, unparalleled.

and lists 7 citations, the earliest from 1610.

Sounds like a contradiction to me.

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pjf | 13 Nov 23:00 2015

See the Colbert interview of Cheng

For a video of Eugenia Cheng on the Stephen Colbert show:

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Jorge Picado | 14 Nov 23:45 2015

PhD Positions, UC|UP Joint PhD Program in Mathematics, Portugal

PhD Positions, UC|UP Joint PhD Program in Mathematics, Portugal

The UC|UP Joint PhD Program in Mathematics, run  by the Universities of Coimbra and Porto,  in Portugal,
welcomes applications for the  academic year 2016/2017.

The Program will offer a number of doctoral  scholarships (covering tuition fees and living  expenses) to
selected candidates. Funding will be made available from the support of the national  agency FCT and the
associated research centers.

All areas of Mathematics are covered in the Program,  in particular:

  Analysis/Differential Equations
  Discrete Mathematics/Combinatorics
  Dynamical Systems
  Numerical Analysis/Optimization

The first call for applications is open from December 1, 2015 to January 31, 2016:

Extensive information about the Program is available  at the website (and additional questions can be
posed using phd_prog <at>


Jorge Picado ::

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pjf | 13 Nov 23:12 2015

Jim Holt on categories

Jim Holt wrote in his "Diary" on Slate, 2000--11--27

    Category theory is a ridiculously abstract framework that takes all
    the meaning out of mathematics.

In his review of Michael Harris's "Mathematics Without Apologies:
Portrait of a Problematic Vocation" (Princeton University Press, 2015)
Holt writes (The New York Review of Books, 2015--12--03):

     ...Grothendieck made [category theory] sing. Between 1958 and 1970,
    he used category theory to create novel structures of unexampled
    richness. Since then, the heady abstractions of category theory
    have also become useful in theoretical physics, computer science,
    logic and philosophy. Footnote: A charming and improbably successful
      attempt to explain category theory in culinary terms is made by
      the mathematician Eugenia Cheng in her new book "How to Bake Pi:
      An Edible Exploriation of the Mathematics of Mathematics" (Basic
      Books, 2015)

(See also Barany's review of Harris on MathSciNet MR3289987)

I do have one quesion: what does "enexampled richness" mean?

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Dan Christensen | 13 Nov 19:51 2015

fully funded graduate positions in Math at UWO

Please distribute to undergraduate and master's students and
appropriate counsellors and supervisors.

                       Graduate Student Positions

                       Department of Mathematics
                     University of Western Ontario
                        London, Ontario, Canada

The Department of Mathematics at the University of Western Ontario
solicits applications for its MSc and PhD programs.  We have up to
20 fully funded positions available, and applicants from any country
are welcome.

Our faculty members supervise research in a variety of areas:

More information, including the application procedure, is available at

Students normally start in September, in which case applications
should be complete (including letters of reference and supplementary
material) by February 15.  Applications received after this deadline
will be reviewed as space permits.  Early applications are welcome,
and we encourage applicants to apply for external scholarships they
are eligible for.

Please contact math-grad-program <at> with any questions you may have.
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Sam Staton | 11 Nov 16:21 2015

LICS 2016 - Call for Workshop Proposals

Call for Workshop Proposals 
LICS 2016 
31st ACM/IEEE Symposium on Logic In Computer Science 

The thirty-first ACM/IEEE Symposium on Logic In Computer Science 
(LICS 2016) will be held in New York City, USA on July 5–8, 2016. It 
will be followed by IJCAI (International Joint Conference on 
Artificial Intelligence). The workshops will take place between the 
two conferences, on July 9–10, 2016. 

Researchers and practitioners are invited to submit proposals for 
workshops on topics relating logic – broadly construed – to computer 
science or related fields. Typically, LICS workshops feature a number 
of invited speakers and a number of contributed presentations. LICS 
workshops do not usually produce formal proceedings. However, in the 
past there have been special issues of journals based in part on 
certain LICS workshops. 

Proposals should include: 

- A short scientific summary and justification of the proposed topic. 
   This should include a discussion of the particular benefits of the 
   topic to the LICS community. 
- A discussion of the proposed format and agenda. 
- The proposed duration, which is typically one day (two-day 
   workshops can be accommodated too). 
- The preferred date. 
- Procedures for selecting participants and papers. 
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