Eduardo J. Dubuc | 1 Apr 19:55 2011
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on_ignorance

Concerning certain sarcastic answers given in this list to some trivial
questions (trivial for the expert, but not trivial for the ignorant), I just
read the following (I ignore the author):

"Productive stupidity means being ignorant by choice. Focusing on important
questions puts us in the awkward position of being ignorant. One of the
beautiful things about science is that it allows us to bumble along, getting
it wrong time after time, and feel perfectly fine as long as we learn
something each time. No doubt, this can be difficult for students who are
accustomed to getting the answers right. No doubt, reasonable levels of
confidence and emotional resilience help, but I think scientific education
might do more to ease what is a very big transition: from learning what
other people once discovered to making your own discoveries. The more
comfortable we become with being stupid, the deeper we will wade into the
unknown and the more likely we are to make big discoveries."

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Ronnie Brown | 3 Apr 16:04 2011

Re: on_ignorance

Perhaps in agreement with Eduardo one should publicise an apochryphal
dedication to a PhD Thesis (learned from Michael Barratt):

"I am deeply grateful to Professor X, whose wrong conjectures and
fallacious proofs, led me to the theorems he had overlooked. "

Good supervision!

I also once felt after a day long discussion with MGB, `If Michael can
try one damn fool thing after another, then so can I.'
Of course they were not so `damn fool' but the thing I learned was the
value of persistence.

Grothendieck was insistent that `Pursuing stacks' should be published
(if at all!) as written, so that young people could see that even very
well known people can and do make mistakes. I found the transition from
undergraduate mathematics to postgraduate mathematics a cultural shock,
and took a long time to get going in research. Thus the methodology of
research is to my mind well worth discussion, even if there is no final
conclusion, except, possibly, things to be avoided.  I put down some
things in the Prefaces to `Topology and Groupoids'. See also Brown and
Porter, ` The methodology of mathematics', on
http://pages.bangor.ac.uk/~mas010/publar.html

G. Spencer-Brown wrote (something like, see wikipedia):

`We teach people to be proud of knowledge and ashamed of ignorance. This
is doubly corrupt, since the natural state is one of ignorance.'

Ronnie
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Marta Bunge | 3 Apr 18:14 2011
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RE: on_ignorance

[Note from moderator: Marta is correct that I was careless is posting 
Eduardo's message. It is not about category theory and is not part of any 
thread I am aware of. Any further discussion will not be on the list. 
Thanks.]

Dear Eduardo,

Is this part of a thread? Are we supposed to search the categories listings to look for what you are exactly
referring to? Do you realize that in so doing we would be taken away from our work or from anything else we
would rather be doing? 

MY guess is that your posting would have been rejected by the moderator had  the author been someone else, and
this for any of the following reasons.  It contains no mathematics, there is no explicit mention of the
context, and an anonymous text is quoted. Moreover, if this belongs to a thread, it is then not a very recent
one and surely as a thread it must have expired. 

If moralizing is to be accepted in categories fro now on, I would offer my own advice. Do not write anything
likely to create (further) divisions in  categories. To mathematics, respond only with mathematics.
Personal remarks - even if laudatory, ought to be forbidden. 

Although a response to a published posting, the moderator should reject this message. I would understand
it perfectly!

Best wishes,

Marta

> Date: Fri, 1 Apr 2011 14:55:51 -0300
> From: edubuc <at> dm.uba.ar
> To: categories <at> mta.ca
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Monika Seisenberger | 4 Apr 13:01 2011
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10th Wessex Theory Seminar, Swansea, 7th April 2011

Dear All,

The 10th Wessex Theory Seminar is taking place at Swansea University on 7 April
2011:
http://wiki.bath.ac.uk/display/wessex/10th+Wessex+Theory+Seminar

Preliminary programme:

           12:30 Lunch

           13:30 Martin Escardo: The Ubiquitous Selection Monad.

           14:10 Paulo Oliva: The Dialectica Interpretation of Classical Logic,
           Arithmetic and Analysis

           14:50 Break

           15:30 Martin Brain: An Algebra of Search Spaces

           16:10 Ondrej Rypajek: Higher Dimensional Type Theory

           16:40 Peter Mosses: PLanCompS - Programming Language Components and
           Specifications

           17:00 Closing

It is still possible to attend.

All welcome.
With best regards, Monika
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Paul Levy | 4 Apr 19:21 2011
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British Colloquium in Theoretical Computer Science - last call for participation

Dear category theorists,

The British Colloquium in Theoretical Computer Science is taking place  
in Birmingham over 18-21 April.

http://events.cs.bham.ac.uk/BCTCS2011/index.html

We have some fantastic invited speakers:

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

 	• David S. Johnson (AT&T Labs)
Bin Packing: From Theory to Experiment and Back Again

 	• Cliff Jones (Newcastle)
What can we do to achieve genuine tool inter-working? Towards a  
"method frame"

 	• Prakash Panangaden (McGill)
Epistemic Strategies and Games on Concurrent Processes

 	• Peter Selinger (Dalhousie)
Logical methods in quantum information theory

 	• Nigel Smart (Bristol)
Homomorphic Encryption

 	• Carsten Witt (Technical University of Denmark)
Bio-Inspired Computation Meets Theoretical Computer Science

(Continue reading)

Olivia Caramello | 5 Apr 02:58 2011
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Preprint: "A topos-theoretic approach to Stone-type dualities"

Dear All,

The following preprint is available from the Mathematics ArXiv at the
address http://arxiv.org/abs/1103.3493:

O. Caramello, "A topos-theoretic approach to Stone-type dualities"

Abstract:

We present an abstract unifying framework for interpreting Stone-type
dualities; several known dualities are seen to be instances of just one
topos-theoretic phenomenon, and new dualities are introduced. In fact,
infinitely many new dualities between preordered structures and locales or
topological spaces can be generated through our topos-theoretic machinery in
a uniform way. We then apply our topos-theoretic interpretation to obtain
results connecting properties of preorders and properties of the
corresponding locales or topological spaces, and we establish adjunctions
between various kinds of categories as natural applications of our general
methodology. In the last part of the paper, we exploit the theory developed
in the previous parts to obtain a topos-theoretic interpretation of the
problem of finding explicit descriptions of models of 'ordered algebraic
theories' presented by generators and relations, and give several examples
which illustrate the effectiveness of our methodology. In passing, we
provide a number of other applications of our theory to Algebra, Topology
and Logic.

This work represents a concrete implementation of the abstract methodologies
introduced in the paper "The unification of Mathematics via Topos Theory",
which I advertised on this list some months ago; incidentally, some
subscribers to this list might be interested in the Russian translation of
(Continue reading)

Ellis D. Cooper | 7 Apr 14:50 2011
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Constitutive Structures

What might be the proper categorical framework to discuss, for
example, the fact that the Real Numbers have constitutive structures
such as additive abelian group, multiplicative abelian group,
topology generated by open intervals, totally ordered infinite set, and so on?
At first one might think of forgetful functors, but then what would
be the category in which Real Numbers is one object among many?
Or, one might say take a category with exactly one object and a
functor to each of the categories of the constitutive structures. This makes
the Real Numbers look like an "element" of the "intersection" of
diverse categories. Then the Complex Numbers or the Hyperreal Numbers
which contain
the Real Numbers as sub-objects in certain ways are "elements" of
other "intersections" of categories. What am I talking about?

Ellis D. Cooper

[For admin and other information see: http://www.mta.ca/~cat-dist/ ]

Tom Leinster | 7 Apr 22:15 2011
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Scottish Category Theory Seminar

***  THE 4TH SCOTTISH CATEGORY THEORY SEMINAR  ***

***  School of Mathematics and Statistics, University of Glasgow  ***
***  Friday 13 May 2011, 2-5.30pm  ***

The Scottish Category Theory Seminar brings together the diverse groups of
people interested in the many aspects of category theory.  For our fourth
meeting we give you:

INVITED SPEAKERS

Eugenia Cheng (Sheffield) - "Distributive laws for Lawvere theories"
Bruno Vallette (Nice/Max Planck) - To be announced.

CONTRIBUTED TALKS

Submissions are invited for two 25-minute contributed talks.  If you would
like to give one, please send us a title and abstract soon.

If you intend to come, it would be helpful (but is not essential) to send
us a short email saying so.

Information: http://www.maths.gla.ac.uk/~tl/sct110513.html
Contact:     scotcats <at> cis.strath.ac.uk

We are generously supported by the Glasgow Mathematical Journal Trust.

Tom Leinster
(for the organizers: Neil Ghani, TL, Alex Simpson)

(Continue reading)

Andrej Bauer | 8 Apr 12:18 2011

Re: Constitutive Structures

You may wish to look at Davorin Lešnik's Ph.D. thesis, where he
studies real numbers in a constructive setting (without choice). He
identifies  suitable categories inside of which the real numbers exist
as an object with a universal property that determines the reals up to
isomorphism. The various categories correspond to the various
substructure of the reals (order, additive group, ring, etc.)

An interesting question is where to find his Ph.D. thesis. I will make
him publish it somewhere on the web and will come back to you with a
link.

With kind regards,

Andrej

On Thu, Apr 7, 2011 at 2:50 PM, Ellis D. Cooper <xtalv1 <at> netropolis.net> wrote:
> What might be the proper categorical framework to discuss, for
> example, the fact that the Real Numbers have constitutive structures
> such as additive abelian group, multiplicative abelian group,
> topology generated by open intervals, totally ordered infinite set, and so
> on?
> At first one might think of forgetful functors, but then what would
> be the category in which Real Numbers is one object among many?
> Or, one might say take a category with exactly one object and a
> functor to each of the categories of the constitutive structures. This makes
> the Real Numbers look like an "element" of the "intersection" of
> diverse categories. Then the Complex Numbers or the Hyperreal Numbers
> which contain
> the Real Numbers as sub-objects in certain ways are "elements" of
> other "intersections" of categories. What am I talking about?
(Continue reading)

Haskell Symposium | 10 Apr 19:29 2011
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CFP -- Haskell Symposium 2011

                      "Haskell 2011"

              ACM SIGPLAN Haskell Symposium 2011
                       Tokyo, Japan
                   22nd September, 2011

                      CALL FOR PAPERS

       http://www.haskell.org/haskell-symposium/2011/

The ACM SIGPLAN Haskell Symposium 2011 will be co-located with the
2011 International Conference on Functional Programming (ICFP), in
Tokyo, Japan.

The purpose of the Haskell Symposium is to discuss experiences with
Haskell and future developments for the language. The scope of the
symposium includes all aspects of the design, semantics, theory,
application, implementation, and teaching of Haskell.

Topics of interest include, but are not limited to:

 * Language Design, with a focus on possible extensions and
   modifications of Haskell as well as critical discussions of the
   status quo;

 * Theory, such as formal treatments of the semantics of the present
   language or future extensions, type systems, and foundations
   for program analysis and transformation;

 * Implementations, including program analysis and transformation,
(Continue reading)


Gmane