You're reading the public-facing archive of the Category Theory Zulip server.
To join the server you need an invite. Anybody can get an invite by contacting Matteo Capucci at name dot surname at gmail dot com.
For all things related to this archive refer to the same person.
John Baez (Jan 11 2021 at 18:20):I just submitted this to the arXiv, but you can get it now:
These are the first 50 issues of This Week's Finds of Mathematical Physics. This series has sometimes been called the world's first blog, though it was originally posted on a "usenet newsgroup'' called sci.physics.research --- a form of communication that predated the world-wide web. I began writing this series as a way to talk about papers I was reading and writing, and in the first 50 issues I stuck closely to this format. These issues focus rather tightly on quantum gravity, topological quantum field theory, knot theory, and applications of n-categories to these subjects. There are, however, digressions into elliptic curves, Lie algebras, linear logic and various other topics.
Tim Hosgood kindly typeset all 300 issues of This Week's Finds in 2020. They will be released in six installments of 50 issues each. I have edited the issues here to make the style a bit more uniform and also to change some references to preprints, technical reports, etc. into more useful arXiv links. This accounts for some anachronisms where I discuss a paper that only appeared on the arXiv later.
The process of editing could have gone on much longer; there are undoubtedly many mistakes remaining. If you find some, please contact me and I will try to fix them.
Tim Hosgood (Jan 11 2021 at 18:43):really happy to see this going up! :tada:
John Baez (Jan 11 2021 at 19:19):Yes, all the thanks go to @Tim Hosgood for making this possible!
I put a lot of time into updating the references and normalizing the style - the first 50 weeks were especially erratic since I was just getting started.
The weirdest bug is due to the arXiv, Tim! Check out the cover page they produced:
This Week's Finds arXiv cover page
John Baez (Jan 11 2021 at 19:20):For right now I'll just accept it as part of the mystery of life.
Tim Hosgood (Jan 11 2021 at 19:21):yes, for me it’s the later weeks that took the time, when you had more ASCII diagrams than I’d ever seen in my life!
Tim Hosgood (Jan 11 2021 at 19:21):hmm, very mysterious indeed...
John Baez (Jan 11 2021 at 19:23):I could it let it drive me crazy, or I could enjoy it. So I'll enjoy it.
Eric Forgy (Jan 11 2021 at 20:23):That is amazing Tim :raised_hands: It's a real tribute :+1: One of my mentors was a student of Charles Misner and has a beautiful dissertation (pre-LaTeX) and converting it to LaTeX for him is on my bucket list :pray: TWFs are awesome :raised_hands: :blush:
John Baez said:
I could it let it drive me crazy, or I could enjoy it. So I'll enjoy it.
I can't resist, "Let it gooo :snowflake: :snowman: " :blush:
Eric Forgy (Jan 11 2021 at 20:31):It looks really nice :heart_eyes: I almost miss the ascii art though. It is nostalgic :smiley:
Nathanael Arkor (Jan 11 2021 at 20:31):John Baez said:
For right now I'll just accept it as part of the mystery of life.
I've seen this happen on other arXiv papers with title pages (e.g. this one).
John van de Wetering (Jan 12 2021 at 10:52):This looks like a really nice resource! Would it be too much of a hassle to add (possibly auto-generate) an index, so that you can more easily find posts on a certain topic?
John Baez (Jan 12 2021 at 16:28):Yes.
John van de Wetering (Jan 12 2021 at 16:29):As in, 'yes, it is too much of a hassle'? :P
Because I can see that
John Baez (Jan 12 2021 at 16:31):Yes. Seriously, that is something I would like to do someday, but first I want to edit all 2610 pages of This Week's Finds and make them available. This will take a while.
John Baez (Jan 12 2021 at 16:31):I may let someone else create an index.
John Baez (Jan 12 2021 at 17:23):I'm more interested in taking certain themes developed in This Week's Finds and turning them into independent essays, so - for example - you can learn about Dynkin diagrams and Coxeter groups and flag varieties (one theme) without having to read this mixed in with other stuff.
Joe Moeller (Jan 12 2021 at 17:55):I don't know if you're using your custom \define command here, but I modified it to automatically generate an index entry on top of the other things it does. I ended up not using it, but I think it should work:
\newcommand{\define}[1]{{\bf \boldmath{#1}}\index{#1}}
Joe Moeller (Jan 12 2021 at 17:56):This alone probably wouldn't be good enough, but it's something.
Matteo Capucci (he/him) (Jan 12 2021 at 18:02):John Baez said:
I'm more interested in taking certain themes developed in This Week's Finds and turning them into independent essays, so - for example - you can learn about Dynkin diagrams and Coxeter groups and flag varieties (one theme) without having to read this mixed in with other stuff.
Indeed, the hypertextual nature of TWF was a plus to me! So many wires crossing!
I could spare some time one day to try to run the LaTeX through pandoc + Jekyll to get an HTML version (which improves on the current by virtue of, I guess, texed math and diagrams), if you wish so.
Tim Hosgood (Jan 12 2021 at 18:20):when i typeset these, i actually started from markdown versions that i then ran pandoc on to get the latex versions
Tim Hosgood (Jan 12 2021 at 18:21):so getting html versions can be done almost for free :)
Tim Hosgood (Jan 12 2021 at 18:21):but john has made a bunch of edits to the latex versions now, so the markdown ones are “outdated”
Tim Hosgood (Jan 12 2021 at 18:22):i think the github repo containing all the markdown versions is public
John van de Wetering (Jan 12 2021 at 20:57):John Baez said:
I may let someone else create an index.
As a suggestion for how this might be done automatically: Generate the tf-idf score for all the words in This Week Finds to figure what the "average number of occurences" is of words in the average post. Then you can see which words occur more often than average by some amount in each post (like terms such as "knot", or "Yang-Baxter"), and you make an entry for this word in the index and point it towards the relevant posts.
John van de Wetering (Jan 12 2021 at 20:57):I have no idea how well this would work
John Baez (Jan 12 2021 at 21:18):There's software for automatically generating indexes, but I've never used it.
Daniel Geisler (Jan 13 2021 at 12:06):@John Baez
Indexing software is a nice intersection of math and programming I should be able to help with. Also, I have a small Perl indexing program that should be close to what is needed.
Tim Hosgood (Jan 13 2021 at 17:15):it's just been pointed out to me that you've called me Tim Silverman in the arXiv abstract (https://arxiv.org/abs/2101.04168), which is a much cooler name, to be fair!
John Baez (Jan 13 2021 at 18:15):Okay. You could try applying it to this TeX file:
http://math.ucr.edu/home/baez/TWF_1-50.tex
I don't promise to have much energy for the indexing project right now...
John Baez (Jan 13 2021 at 18:29):Ugh! Tim Silverman is the guy who is always teaching me about finite groups on the n-Category Cafe. I guess my fingers just took over from my brain while I was typing that. I'll fix it.
John Baez (Jan 17 2021 at 04:54):?
Daniel Geisler (Jan 17 2021 at 06:01):Sorry, I'll have a functional index for the first fifty weeks of TWF in a few days.
John Baez (Jan 17 2021 at 16:22):Cool!
Daniel Geisler (Jan 23 2021 at 08:02):Well, it will take more than a few days to index TWF (1-50) as I am looking at parsing PDF, HTML and ASCII formats to best effect.
Daniel Geisler (Jan 29 2021 at 06:02):I have a Perl script for the index, but I now need to get a book on indexing books.
Daniel Geisler (Feb 03 2021 at 06:21):@John Baez @John van de Wetering The current fifty released TWF contain around 7800 words, but I recommend I write a file for manually excluding words. For example the context of "representation" can be regular English or mathematics for representation theory. I am willing to work on the index as well as maps. If this is not a good time I can help in the future.
John Baez (Feb 03 2021 at 15:57):Interesting - thanks! It's worth having an approach that scales well, because while the first 50 weeks are 242 page, all 300 weeks have been converted to latex, and they're a total of 2610 pages - over 10 times as much. I still need to edit the rest, and that will take a long time. I'm not sure I'll ever want to go through all 2610 pages and manually exclude certain words.
John Baez (Feb 03 2021 at 15:58):I might pay an indexer to work on this....
Daniel Geisler (Feb 04 2021 at 12:24):@John Baez I just picked up Indexing Books, Second Edition, a real nerd toy. I'll provide a preliminary index.
I recommend a three-state system for index entries - unknown classification, English dictionary and finally TWF dictionary. Initially everything would be unclassified. I would go though the word list first and assign all entries I could. An expert could then come through and assign the remaining unknown classifications.
John Baez (Feb 16 2021 at 17:17):Great, thanks! I'd never heard of that book, but I have heard that when people do their own indexes they tend to be not as good as professional indexers'. So this may teach the tricks for doing it right.