Comments on a wikipedia article on a Timeline of Category theory

Comments on a wikipedia article on a Timeline of Category theory

[Ronnie Brown]

We would like to draw the attention of readers of this list to the article

http://en.wikipedia.org/wiki/Timeline_of_category_theory_and_related_mathematics


We feel that this entry is slanted, unbalanced, and in many cases wrong.
It gives credit to work at a given time often presented in the form of
vague ambitious titles or conclusions that give no information on the
actual theorems the authors either claimed or published at the time.  It
fails to give credit to many authors for their contribution to the
development of category theory and its wider applications, and fails to
describe many developments in the area.

It also fails to give references, which is usually a requirement for
wikipedia articles, and the `discussion' makes it clear that the
author(s) of this entry have no intention of so doing, and have not done
so since the entry was made in 2009.

The anonymity of the entry is also a handicap.

One of us has tried to make a correction, but this is using a sticking
plaster on too great a problem. The entry fails to come up to the
standards of wikipedia in scholarship, accuracy and presentation, is not
really possible to correct,  and should therefore be removed.

We would be grateful for comments on this matter, and for agreement to
support this proposal to wikipedia.

Ronnie Brown

George Janelidze




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

Comments on a wikipedia article on a Timeline of Category theory

[Joyal, André]

Dear Ronnie and Georges,

I had a quick glimpse on the wikipedia timeline of category theory.
It can be criticised on many aspects, for example, for its inaccuracies.
But it has also a good side.
It shows for example that a lot of category theory has been developed
by mathmaticians who are not formally category theorists.

I suggest you propose an alternative timeline to the categorical community
before the destruction of this one. 
An imperfect timeline is better than none.

Best, 
André




-------- Message d'origine--------
De: Ronnie Brown [mailto:ronnie.profbrown@btinternet.com]
Date: jeu. 07/07/2011 09:14
À: categories@mta.ca; George Janelidze
Objet : categories: Comments on a wikipedia article on a Timeline of Category theory
 
We would like to draw the attention of readers of this list to the article

http://en.wikipedia.org/wiki/Timeline_of_category_theory_and_related_mathematics


We feel that this entry is slanted, unbalanced, and in many cases wrong.
It gives credit to work at a given time often presented in the form of
vague ambitious titles or conclusions that give no information on the
actual theorems the authors either claimed or published at the time.  It
fails to give credit to many authors for their contribution to the
development of category theory and its wider applications, and fails to
describe many developments in the area.

It also fails to give references, which is usually a requirement for
wikipedia articles, and the `discussion' makes it clear that the
author(s) of this entry have no intention of so doing, and have not done
so since the entry was made in 2009.

The anonymity of the entry is also a handicap.

One of us has tried to make a correction, but this is using a sticking
plaster on too great a problem. The entry fails to come up to the
standards of wikipedia in scholarship, accuracy and presentation, is not
really possible to correct,  and should therefore be removed.

We would be grateful for comments on this matter, and for agreement to
support this proposal to wikipedia.

Ronnie Brown

George Janelidze


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

Re: Comments on a wikipedia article on a Timeline of Category theory

[Andree Ehresmann]

I completely agree with Ronnie and George.
.
For the history, in 2009 I had exchanges of mails with Rafael
Borowiecki (who also used the nickname of Hasse Riemann). I did not
know him but he wrote that he was publishing a timeline and sent me a
lot of questions about the works of Charles Ehresmann and myself on
categories. I took a lot of time to respond to him in details, with
corrections to some of his assertions and proposal of new entries.
Since then I had no news from him, and most of the information I sent
him does not appear in the present timeline.

Andree

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Re: Comments on a wikipedia article on a Timeline of Category theory

[Sergei SOLOVIEV]

I agree that it very much unbalanced - for example, practically all
works on applications
of proof theory to categories are absent. I think that in fact the number of
contributors worth mentioning is maybe 5 times greater, and the idea
to make
a table like in this artikle will generate controverse in any case.

Best

Sergei Soloviev

Ronnie Brown wrote:
> We would like to draw the attention of readers of this list to the
> article
>
> http://en.wikipedia.org/wiki/Timeline_of_category_theory_and_related_mathematics
>
>
>
> We feel that this entry is slanted, unbalanced, and in many cases wrong.
> It gives credit to work at a given time often presented in the form of
> vague ambitious titles or conclusions that give no information on the
> actual theorems the authors either claimed or published at the time.  It
> fails to give credit to many authors for their contribution to the
> development of category theory and its wider applications, and fails to
> describe many developments in the area.
>
> It also fails to give references, which is usually a requirement for
> wikipedia articles, and the `discussion' makes it clear that the
> author(s) of this entry have no intention of so doing, and have not done
> so since the entry was made in 2009.
>
> The anonymity of the entry is also a handicap.
>
> One of us has tried to make a correction, but this is using a sticking
> plaster on too great a problem. The entry fails to come up to the
> standards of wikipedia in scholarship, accuracy and presentation, is not
> really possible to correct,  and should therefore be removed.
>
> We would be grateful for comments on this matter, and for agreement to
> support this proposal to wikipedia.
>
> Ronnie Brown
>
> George Janelidze
>


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

Re: Comments on a wikipedia article on a Timeline of Category theory

[Robert Dawson]

 	This is the sort of article that Wikipedia necessarily does badly at -
as anybody who thinks about it for a few minutes must realize would be
the case.

 	An ad hoc committee not in regular communication can often do a very
good job of putting together a collection of facts.  Connections between
facts are harder because they are often not explicitly in the literature
- and Wikipedia [correctly - there are other fora for that] discourages
"original research" and "opinion".  Similarly, balanced emphasis in long
articles is difficult because (as intended) no one person writes all of
it, and if the person writing about non-normal whiffle theorists has
more spare time and enthusiasm than the person writing on quasinormal
whiffle theorists, the non-normal group end up with disproportionate
coverage. (For obvious reasons, the less-prolific writer would not be
popular if [s]he ripped out an inexpert selection of several hours of
the other writer's work to correct this!)  And omissions are
problematic. In a good single-author article, we could conclude that if
there was nothing about X's contributions to the field, they were
probably quite minor.  A Wikipedia article does not permit this deduction.

 	Can't we just accept that Wikipedia has its weaknesses as well as its
strengths?  For instance, in a paper encyclopedia you would be lucky to
find an article on category theory at all; Wikipedia does not have to
keep within (say) 15,000 pages for all topics.

 	This article is probably fairly reliable on who _was_ working on what
when; it should not be trusted for who was _not_ working on something,
or whose work was most important, and may be dubious on priority.  To
damn it for this is like damning a thesaurus for not being an
etymological dictionary - a sign that somebody is contemplating using a
specialized tool for the wrong purpose.

 	Robert Dawson



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Re: Comments on a wikipedia article on a Timeline of Category theory

[Valeria de Paiva]

Dear Ronnie, and all,

In the internet there is no *removing* of any information, as you suggest,
at all. The only way to remove anything (ask celebrities PR people) is to
add new information that supersedes the undesired one. I suggest applying as
many band-aids as are necessary as soon as possible. Believe me, I just
spent 3 years working for a search engine...

Best regards,
Valeria

On Thu, Jul 7, 2011 at 6:14 AM, Ronnie Brown <
ronnie.profbrown@btinternet.com> wrote:

> We would like to draw the attention of readers of this list to the article
>
> http://en.wikipedia.org/wiki/**Timeline_of_category_theory_**
> and_related_mathematics<http://en.wikipedia.org/wiki/Timeline_of_category_theory_and_related_mathematics>
>
>
> We feel that this entry is slanted, unbalanced, and in many cases wrong.
> It gives credit to work at a given time often presented in the form of
> vague ambitious titles or conclusions that give no information on the
> actual theorems the authors either claimed or published at the time.  It
> fails to give credit to many authors for their contribution to the
> development of category theory and its wider applications, and fails to
> describe many developments in the area.
>
> It also fails to give references, which is usually a requirement for
> wikipedia articles, and the `discussion' makes it clear that the
> author(s) of this entry have no intention of so doing, and have not done
> so since the entry was made in 2009.
>
> The anonymity of the entry is also a handicap.
>
> One of us has tried to make a correction, but this is using a sticking
> plaster on too great a problem. The entry fails to come up to the
> standards of wikipedia in scholarship, accuracy and presentation, is not
> really possible to correct,  and should therefore be removed.
>
> We would be grateful for comments on this matter, and for agreement to
> support this proposal to wikipedia.
>
> Ronnie Brown
>
> George Janelidze


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

Re: Comments on a wikipedia article on a Timeline of Category theory

[Peter Selinger]

I was intrigued by the question of who composed this Wikipedia
"timeline of category theory". A closer look at the article's history
shows that the list of entries was almost entirely created by a single
user, "Fotino", between September 2008 and July 2009. There was one
other user from Sweden (IP address 83.233.242.29) who contributed a
large number of entries in May 2009. That might have just been Fotino
having forgotten to log in that day. Only three entries (on Brower,
Heyting, and Serre) were later added by other people. Although many
other users contributed changes, all of them just edited existing
entries in the list.

I think that Fotino, whoever he or she is, should be commended for
what was obviously a non-trivial amount of work. He or she hasn't
contributed anything else to Wikipedia besides this one article, so it
must have really been a work of passion.

Of course, any such list will be subject to criticism and possible
improvement. I completely agree with Ronnie and George that the
article would benefit from references, as per Wikipedia's
policy. Also, no survey or timeline written by a single person will
include everything that should be included, or exclude everything that
should be excluded.

Ironically, Fotino him- or herself had a similar gripe with another
article, "Timeline of mathematics", where he/she wrote on the
discussion page in June 2009:

  "There is no name of grothendieck and hence the list is not
  serious. [...]. the list has to be removed completely. [...] In my
  oppinion almost everything in modern mathematics is missing, not only
  category theory, but also for instance analysis. But the blame can
  not be put wholely on the creator of the timeline but on all who
  could include these things but don't. [...]. Yes, i have some entries
  to include, but i don't have the time."

I guess we can deduce from this that Fotino would be very happy for
others to contribute to his article. -- Peter

Ronnie Brown wrote:
>
> We would like to draw the attention of readers of this list to the article
>
> http://en.wikipedia.org/wiki/Timeline_of_category_theory_and_related_mathematics
>
>
> We feel that this entry is slanted, unbalanced, and in many cases wrong.
> It gives credit to work at a given time often presented in the form of
> vague ambitious titles or conclusions that give no information on the
> actual theorems the authors either claimed or published at the time.  It
> fails to give credit to many authors for their contribution to the
> development of category theory and its wider applications, and fails to
> describe many developments in the area.
>
> It also fails to give references, which is usually a requirement for
> wikipedia articles, and the `discussion' makes it clear that the
> author(s) of this entry have no intention of so doing, and have not done
> so since the entry was made in 2009.
>
> The anonymity of the entry is also a handicap.
>
> One of us has tried to make a correction, but this is using a sticking
> plaster on too great a problem. The entry fails to come up to the
> standards of wikipedia in scholarship, accuracy and presentation, is not
> really possible to correct,  and should therefore be removed.
>
> We would be grateful for comments on this matter, and for agreement to
> support this proposal to wikipedia.
>
> Ronnie Brown
>
> George Janelidze
>
>
>
>
> [For admin and other information see: http://www.mta.ca/~cat-dist/ ]
>



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

Re: Comments on a wikipedia article on a Timeline of Category theory

[Toby Bartels]

Peter Selinger wrote in part:

>I was intrigued by the question of who composed this Wikipedia
>"timeline of category theory". A closer look at the article's history
>shows that the list of entries was almost entirely created by a single
>user, "Fotino", between September 2008 and July 2009.

Fotino is Rafael Borowiecki, who also contributed the timeline to the nLab:
http://ncatlab.org/nlab/show/Timeline+of+category+theory+and+related+mathematics
There it has received some edits and criticism, but was mostly ignored,
and in fact has not yet had the wiki-syntax fully converted yet.


--Toby


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Re: Comments on a wikipedia article on a Timeline of Category theory

[Eduardo J. Dubuc]

Before the net and wikipedia the only people which had the possibility
of a large audience where "the authorities", prestigious people on their
field.

We all were bounded by their view of things.

Now everybody interested have the same chance to expose his (or hers)
own version of a  subject.

Both situations have their positive and negative aspects.

I much prefer how thing are now.

No censorship to wikipedia !




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Timelines for category theory: a response to comments

[Ronnie Brown]

Dear Colleagues,

Many thanks for your comments, which show how our community sees the
problem. The discussion is obviously not finished yet.

Let us actually try to say what is the MAIN problem with this article.
The main problem is the picture of category theory it draws! Many of you
give courses in category theory at various levels - beautiful courses
showing that category theory provides a new most advanced level of
thinking in mathematics ("thinking categorically!"), and has made major
contributions to the unity of mathematics. So, why don't you compare the
plan of your own course with this article? Surely you do not begin your
course with resolutions of modules and you do not end it with "extended
TQFT", do you?

On the other hand there is clearly a desire to have a good content  and
context for category theory on wikipedia, which is often the first port
of call for students, and those potentially interested, and so there are
calls for an improved Timeline for category theory. To take in the whole
subject in one timeline, with references, would seem an enormous and
controversial task.

We therefore propose that the present article be replaced by  a list of
topics with links to articles on timelines of those topics. And then
each "timeline" should be written by a chosen group of experts. Our
first draft of topics would be:

1. General category theory, including motivation
2. Abelian categories and homological algebra
3. Categories and groupoids in homotopical algebra and algebraic topology
4. Topos theory
5. Monoidal, enriched, and higher-dimensional categories
6. Categorical algebra
7. Categorical topology
8. Categorical logic and foundation of mathematics
10. Categories in algebraic geometry
11. Categories in computer science
12. Categories in Physics

There will be intersections of course, but we presume that is fine.

As examples of timelines in other subjects, and their styles, see for
example

http://en.wikipedia.org/wiki/List_of_timelines#Science

particularly those on Physics.

We look forward to reactions to this proposal.

Ronnie Brown

George Janelidze


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

Re: Timelines for category theory: a response to comments

[jim stasheff]

On 7/10/11 1:03 PM, Ronnie Brown wrote:
> 1. General category theory, including motivation
Trivial but important suggestion

add

0. Motivation for cat theory

   before anything technical

maybe that can be a compilation of motivationS derived from the other topics


jim



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Re: Timelines for category theory: a response to comments

[Robert Dawson]

Ronnie Brown wrote:

> We therefore propose that the present article be replaced by a list of
> topics with links to articles on timelines of those topics. And then
> each "timeline" should be written by a chosen group of experts. Our
> first draft of topics would be:

 	Ronnie:

 		No doubt the project you have described is an excellent one, but
"propose that the article be replaced" just isn't how Wikipedia works -
let alone "should be written by a chosen group of experts."

 	This is like suggesting that a school talent show would be better if
instead of having all those random kids singing & dancing they hired
some real professionals.  Or like saying MacDonald's would be a great
restaurant if they ditched the burgers and chips.

 	There's nothing stopping you from putting together the project you
describe; and some parts of it could be accomplished on Wikipedia. But
why?  It could not be exactly what you want, and conversely you don't
seem to think the Wikipedia model is very useful for what you would like
to do.  There are lots of other Internet service providers out there.

 	Cheers,
 		Robert





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Re: Timelines for category theory: a response to comments

[Sergei SOLOVIEV]

I think that the list of topics is very good, and the idea seems to me
very reasonnable.

And with all my respect to Eduardo ("No censorship to wikipedia !") I
don't think
that everything should be reduced to mere opinions and freedom of speech
- there is
also the notion of truth. Supposedly, the above mentioned freedom should
help
to find it, at least, in science.

Best regards

Sergei Soloviev

Ronnie Brown wrote:
> Dear Colleagues,
>
> Many thanks for your comments, which show how our community sees the
> problem. The discussion is obviously not finished yet.
>
> Let us actually try to say what is the MAIN problem with this article.
> The main problem is the picture of category theory it draws! Many of you
> give courses in category theory at various levels - beautiful courses
> showing that category theory provides a new most advanced level of
> thinking in mathematics ("thinking categorically!"), and has made major
> contributions to the unity of mathematics. So, why don't you compare the
> plan of your own course with this article? Surely you do not begin your
> course with resolutions of modules and you do not end it with "extended
> TQFT", do you?
>
> On the other hand there is clearly a desire to have a good content  and
> context for category theory on wikipedia, which is often the first port
> of call for students, and those potentially interested, and so there are
> calls for an improved Timeline for category theory. To take in the whole
> subject in one timeline, with references, would seem an enormous and
> controversial task.
>
> We therefore propose that the present article be replaced by  a list of
> topics with links to articles on timelines of those topics. And then
> each "timeline" should be written by a chosen group of experts. Our
> first draft of topics would be:
>
> 1. General category theory, including motivation
> 2. Abelian categories and homological algebra
> 3. Categories and groupoids in homotopical algebra and algebraic topology
> 4. Topos theory
> 5. Monoidal, enriched, and higher-dimensional categories
> 6. Categorical algebra
> 7. Categorical topology
> 8. Categorical logic and foundation of mathematics
> 10. Categories in algebraic geometry
> 11. Categories in computer science
> 12. Categories in Physics
>
> There will be intersections of course, but we presume that is fine.
>
> As examples of timelines in other subjects, and their styles, see for
> example
>
> http://en.wikipedia.org/wiki/List_of_timelines#Science
>
> particularly those on Physics.
>
> We look forward to reactions to this proposal.
>
> Ronnie Brown
>
> George Janelidze


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

Re: Timelines for category theory: a response to comments

[David Roberts]

Hi Ronnie,

> ....Our first draft of topics would be:
>
> 1. General category theory, including motivation
> 2. Abelian categories and homological algebra
> 3. Categories and groupoids in homotopical algebra and algebraic topology
> 4. Topos theory
> 5. Monoidal, enriched, and higher-dimensional categories
> 6. Categorical algebra
> 7. Categorical topology
> 8. Categorical logic and foundation of mathematics
> 10. Categories in algebraic geometry
> 11. Categories in computer science
> 12. Categories in Physics


a good candidate for what your 12., combined with 11., 8. and a bit of 5.  might
look like is Baez and Stay's 'Rosetta stone' paper, see:

http://golem.ph.utexas.edu/category/2008/03/physics_topology_logic_and_com.html

Clearly this is only a tiny slice of the category theory cake, and perhaps again
a biased one, but at least it contains facts, and references.

Best of luck with this project, I look forward to contributing in what small way
I can.

David


------------------------------
David Roberts

david.roberts@adelaide.edu.au
University of Adelaide



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Re: Timelines for category theory: a response to comments

[Jeremy Gibbons]

If I may stick my head over the parapet, I'd like to suggest that you're surely fighting a losing battle here. Wikipedia does not work by having articles written by "chosen groups of experts". Indeed, quite the opposite; some amateur with community spirit and a personal itch to scratch makes a start, others - perhaps more expert - chip in, and gradually the wonder that is Wikipedia blossoms. Or not, as the case may be: perhaps two amateurs with conflicting axes to grind hack away at each other's changes, and nothing productive comes of it; that's the price you pay for crowd-sourcing.

I believe that your only option is to do some of that chipping in yourself. You can obviously see many flaws in the original article that "Fotino" has kindly started; why not set about improving it? Who knows - others may follow your noble example! 

But I recommend not to start by replacing the existing article with a blank slate; that's simply rude. If in doubt, start with the associated discussion page, which doesn't seem to have changed since Oct 2009. See the discussion under "Stub requests"; maybe talk personally with Charles Matthews.

Jeremy

On 10 Jul 2011, at 18:03, Ronnie Brown wrote:

> Dear Colleagues,
> 
> Many thanks for your comments, which show how our community sees the
> problem. The discussion is obviously not finished yet.
> 
> Let us actually try to say what is the MAIN problem with this article.
> The main problem is the picture of category theory it draws! Many of you
> give courses in category theory at various levels - beautiful courses
> showing that category theory provides a new most advanced level of
> thinking in mathematics ("thinking categorically!"), and has made major
> contributions to the unity of mathematics. So, why don't you compare the
> plan of your own course with this article? Surely you do not begin your
> course with resolutions of modules and you do not end it with "extended
> TQFT", do you?
> 
> On the other hand there is clearly a desire to have a good content  and
> context for category theory on wikipedia, which is often the first port
> of call for students, and those potentially interested, and so there are
> calls for an improved Timeline for category theory. To take in the whole
> subject in one timeline, with references, would seem an enormous and
> controversial task.
> 
> We therefore propose that the present article be replaced by  a list of
> topics with links to articles on timelines of those topics. And then
> each "timeline" should be written by a chosen group of experts. Our
> first draft of topics would be:
> 
> 1. General category theory, including motivation
> 2. Abelian categories and homological algebra
> 3. Categories and groupoids in homotopical algebra and algebraic topology
> 4. Topos theory
> 5. Monoidal, enriched, and higher-dimensional categories
> 6. Categorical algebra
> 7. Categorical topology
> 8. Categorical logic and foundation of mathematics
> 10. Categories in algebraic geometry
> 11. Categories in computer science
> 12. Categories in Physics
> 
> There will be intersections of course, but we presume that is fine.
> 
> As examples of timelines in other subjects, and their styles, see for
> example
> 
> http://en.wikipedia.org/wiki/List_of_timelines#Science
> 
> particularly those on Physics.
> 
> We look forward to reactions to this proposal.
> 
> Ronnie Brown
> 
> George Janelidze
> 

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

Re: Timelines for category theory: a response to comments

[Graham White]

I think, judging by comments so far, that there are basically two
goals concealed within "this project". One is to write an outline of
category theory as it seems to us now; the other is to write a history
of category theory, and, specifically, a history of who influenced whom.
Both of these are very worth doing, but the second is much more
difficult.

It's difficult mainly because it entails recovering a consistent history
from people's reminiscences, and these will not be consistent with
each other: they will be inconsistent not just because people's memories
are not accurate, but because everyone has remained active in the field
and they alter their memories according to what they think now. This is
probably especially true of mathematicians, because mathematicians
always rephrase other people's stuff in their own terms: it's how they
come to understand it. (Remember Goethe's remark, "Mathematicians are
like Frenchmen: if you tell them something, they rephrase it in their
own language, and you cannot understand it any more"? Well,
mathematicians do that to each other as well as to non-mathematicians).

The history is hard to do, but also potentially very valuable: it would
show how a revolution in mathematics took place. Hard work, though.

And *not* in the form of a Wiki, because Wikis deal with contradictions
between documents by erasing one document in favour of the other. (I
know, you can always look back in edit history, but it still relegates
one of the testimonies to the sidelines: you might well be in a
situation where you just have more than one testimony, and where it
would not be sensible to prefer one to the other).

Graham

On Tue, Jul 12, 2011 at 06:48:53AM +0930, David Roberts wrote:
> Hi Ronnie,
>
>> ....Our first draft of topics would be:
>>
>> 1. General category theory, including motivation
>> 2. Abelian categories and homological algebra
>> 3. Categories and groupoids in homotopical algebra and algebraic topology
>> 4. Topos theory
>> 5. Monoidal, enriched, and higher-dimensional categories
>> 6. Categorical algebra
>> 7. Categorical topology
>> 8. Categorical logic and foundation of mathematics
>> 10. Categories in algebraic geometry
>> 11. Categories in computer science
>> 12. Categories in Physics
>
>
> a good candidate for what your 12., combined with 11., 8. and a bit of 5.  might
> look like is Baez and Stay's 'Rosetta stone' paper, see:
>
> http://golem.ph.utexas.edu/category/2008/03/physics_topology_logic_and_com.html
>
> Clearly this is only a tiny slice of the category theory cake, and perhaps again
> a biased one, but at least it contains facts, and references.
>
> Best of luck with this project, I look forward to contributing in what small way
> I can.
>
> David
>

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Re: Comments on a wikipedia article on a Timeline of Category theory

[peasthope]

From:	"Eduardo J. Dubuc" <edubuc@dm.uba.ar>
Date:	Sat, 09 Jul 2011 16:48:59 -0300
> Before the net and wikipedia the only people which had the possibility
> of a large audience where "the authorities", prestigious people on their
> field.
> We all were bounded by their view of things.
>
> Now everybody interested have the same chance to expose his (or hers)
> own version of a  subject.

Reminiscent of this paragraph.
   "http://en.wikipedia.org/wiki/Democratization#Knowledge"

From:	Graham White <graham@eecs.qmul.ac.uk>
Date:	Tue, 12 Jul 2011 17:13:34 +0100
> ... two goals concealed within "this project". One is to write an outline of
> category theory as it seems to us now; ...

Reminiscent of this article.
   "http://en.wikipedia.org/wiki/Outline_of_category_theory"

Best regards to everyone,            ... Peter E.

-- 
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Re: Re: Timelines for category theory: a response to comments

[Patrik Eklund]

Can we do history of category theory without considering history leading 
to category theory? Is history an attachment of subhistories, or are 
there paths that can be followed, and how do we teach these things to 
young researchers? What I say is I like the '... and foundations of 
mathematics'.

I always wondered if the term 'categorical this-and-that' every once 
in a while should be considered with its counterpart 'this-and-thatical 
category theory'. It's also about meta and object languages, I believe.
And sometimes categorists 'internalize', so that the roles of meta and 
object ar blurred. Isn't a topos basically a 'logical category', where 
'categorical logic' is something else? 'Topological category' is not the 
same as 'categorical topology', and so on.

Also, 'categories in computer science' is too general. Still, most of 
categories, used in recognized areas in computer science, relate to logic 
in one way or the other, and to logic in a broad sense. Sometimes we also 
say computer science has given many interesting problems for category 
theory. I don't think this is really true in such a phrasing. What has 
happened is that computer scientist in their work to formalize computable 
logic and computability has been forced to go back to foundations of 
mathematics in order to understand what is really going on. Computer 
scientists, however, usually don't bother to formalize something they 
already 'understand' (type theory is a good example), where a
mathematicians refuses to understand before it's formalized (that's why 
there isn't any mathematical type theory).

Yes, we can. We can do history of category theory without considering 
history leading to category theory. But why should we? And how does it 
help to bring out all flavours of things we are still working on? Will 
this history writing provide me with those utensils I need for things I 
need to do. Or do I have to go elsewhere to look for it?

History writing is also a bit dangerous as it almost says this is now the 
state-of-the-art, and if you don't play your etudes properly you are not 
allowed to play structure and provide interpration. Talent is 
thereby often surpressed, and mostly by teachers who really never 
understood counterpoint anyway.

So what I really say is I like the '... and foundations of mathematics'. 
Keeping meta and object apart, and category theory taught me how to 
do that, is important for logic and foundations, as we know e.g. from 
Gödel numbering and creating sentences about it. To which logic these 
sentences belong, nobody ever told me, so please do.

Best regards,

Patrik



On Tue, 12 Jul 2011, Graham White wrote:

> I think, judging by comments so far, that there are basically two
> goals concealed within "this project". One is to write an outline of
> category theory as it seems to us now; the other is to write a history
> of category theory, and, specifically, a history of who influenced whom.
> Both of these are very worth doing, but the second is much more
> difficult.
>
> It's difficult mainly because it entails recovering a consistent history
> from people's reminiscences, and these will not be consistent with
> each other: they will be inconsistent not just because people's memories
> are not accurate, but because everyone has remained active in the field
> and they alter their memories according to what they think now. This is
> probably especially true of mathematicians, because mathematicians
> always rephrase other people's stuff in their own terms: it's how they
> come to understand it. (Remember Goethe's remark, "Mathematicians are
> like Frenchmen: if you tell them something, they rephrase it in their
> own language, and you cannot understand it any more"? Well,
> mathematicians do that to each other as well as to non-mathematicians).
>
> The history is hard to do, but also potentially very valuable: it would
> show how a revolution in mathematics took place. Hard work, though.
>
> And *not* in the form of a Wiki, because Wikis deal with contradictions
> between documents by erasing one document in favour of the other. (I
> know, you can always look back in edit history, but it still relegates
> one of the testimonies to the sidelines: you might well be in a
> situation where you just have more than one testimony, and where it
> would not be sensible to prefer one to the other).
>
> Graham
>

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Re: Comments on a wikipedia article on a Timeline of Category theory

[Messing]

Concerning Fred Linton's comment about Wikipedia entries in general and
Andre's comment about the categories timeline entry in prticular:

1) The 11th edition of the Britanica, with entries written by ad signed
by Bertrand Russell and other philosophical and intellectual luminaries
is justly renowned.  The French analogue, the Enclyclopedie Universalis
with many of the mathematical articles written by and signed by Jean
Dieudonne is equally distinguished (see in particular Dieudonne's entry
on analytic number theory).  That Wikipedia can not compare is obvious.
     Nevertheless, in my view, it has its uses.  While the entries on
etale or crystalline cohomology were not written by Grothendieck, Artin,
Deligne or Berthelot, they contain for non-experts some insights and
supply references.  The idiom "let the buyer beware" is apt here.

2) I agree with Andre.  An imperfect timeline can be corrected and
improved upon, but it is an initial effort.  By definition, any timeline
is a skeletal outline and, by its very nature, can never be a definitive
historical text concerning whatever it concerns itself with.

Let me take a specific example not mentioned in the Wikipedia timeline.
    In the late 1970's Goresky-Macpherson invented the theory of perverse
sheaves.  This theory was further developed by many others and in
particular, Beilinson-Berstein-Deligne in Asterisque 100.  What is "well
known" to those who have looked at this text's introduction is that
Gabber was to be a fourth author of this monograph, but he refused to
let his name appear, because he thought that the other three authors
were not sufficiently careful with regard to (technical) foundational
questions.  As I do not know who created the current Wikipedia timeline,
I do not know if this individual knows or cares what a perverse sheaf is.

Bill Messing


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Re: Comments on a wikipedia article on a Timeline of Category theory

[Fred E.J. Linton]

George, Ronnie, et al.,

I think you are engaged in a valiant, but losing, battle. 

Tellingly, just today, in my postal mail, I found a copy of 
the latest issue of The New Yorker, with its mini-biography 
of Jaron Lanier, and his reported lamentation of Wikipedia 
as "a triumph of 'intellectual mob rule'".

(See "Issue of July 11 & 18, 2011", pp. 46-53, esp. p. 46.)

I hold out no hope of seeing much improvement in the parts
of Wikipedia that need improving, and I (for one) have now
given up trying. 

Far be it from me to try to dissuade you, though. So:

Cheers, and best of luck in any event, -- Fred

------ Original Message ------
Received: Thu, 07 Jul 2011 07:51:00 PM EDT
From: Ronnie Brown <ronnie.profbrown@btinternet.com>
To: "categories@mta.ca" <categories@mta.ca>,        George Janelidze
<janelg@telkomsa.net>
Subject: categories: Comments on a wikipedia article on a Timeline of Category
theory

> We would like to draw the attention of readers of this list to the article
> 
>
http://en.wikipedia.org/wiki/Timeline_of_category_theory_and_related_mathematics
> 
> 
> We feel that this entry is slanted, unbalanced, and in many cases wrong.
> It gives credit to work at a given time often presented in the form of
> vague ambitious titles or conclusions that give no information on the
> actual theorems the authors either claimed or published at the time.  It
> fails to give credit to many authors for their contribution to the
> development of category theory and its wider applications, and fails to
> describe many developments in the area.
> 
> It also fails to give references, which is usually a requirement for
> wikipedia articles, and the `discussion' makes it clear that the
> author(s) of this entry have no intention of so doing, and have not done
> so since the entry was made in 2009.
> 
> The anonymity of the entry is also a handicap.
> 
> One of us has tried to make a correction, but this is using a sticking
> plaster on too great a problem. The entry fails to come up to the
> standards of wikipedia in scholarship, accuracy and presentation, is not
> really possible to correct,  and should therefore be removed.
> 
> We would be grateful for comments on this matter, and for agreement to
> support this proposal to wikipedia.
> 
> Ronnie Brown
> 
> George Janelidze
> 

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