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van Ekeren, Möller, Scheithauer on holomorphic orbifolds
*August 31, 2015*

*Posted by Scott Carnahan in Uncategorized.*

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There aren’t many blog posts about vertex operator algebras, so I thought I’d help fill this gap by mentioning a substantial advance by Jethro van Ekeren, Sven Möller, and Nils Scheithauer that appeared on the ArXiv last month. The most important feature is that this paper resolves several folklore conjectures that have been around since near the beginning of vertex operator algebra theory. This was good for me, since I was able to use some of these results to prove the Generalized Moonshine Conjecture much more quickly than I had expected. I won’t say much about moonshine here, as I think it deserves its own post.

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Announcing ALGECOM Fall 2015
*August 19, 2015*

*Posted by David Speyer in Uncategorized.*

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The University of Michigan at Ann Arbor is proud to be hosting

ALGECOM, the twice annual midwestern conference on algebra, geometry

and combinatorics on Saturday, October 24. We will feature four

speakers, namely,

Jonah Blasiak (Drexel University)

Laura Escobar (University of Illinois at Urbana-Champaign)

Joel Kamnitzer (University of Toronto)

Tri Lai (IMA and University of Minnesota)

as well as a poster session. If you would like to submit a poster, please e-mail (David Speyer) with a quick summary of your work by September 15.

A block of rooms has been reserved at the (Lamp Post Inn) under the name of ALGECOM.

This conference is supported by a conference grant form the NSF. Limited funds are available for graduate student travel to the conference. Please contact (David Speyer) to request support, and include a note from your adviser.

More information will be added to our website as it becomes available.

We hope to see you there!

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The dishonest stopping paradox
*May 10, 2015*

*Posted by David Speyer in Uncategorized.*

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A number of blogs I read are arguing about a paradox, posed by tumblr blogger perversesheaf. Here is my attempt to explain what the paradox says.

Suppose that a drug company wishes to create evidence that a drug is beneficial, when in fact its effect is completely random. To be concrete, we’ll say that the drug has either positive or negative effect for each patient, each with probability . The drug company commits in advance that they will state exactly what their procedure will be, including their procedure for when to stop tasks, and that they will release all of their data. Nonetheless, they can guarantee that a Bayesian analyst with a somewhat reasonable prior will come to hold a strong belief that the drug does some good. Below the fold, I’ll explain how they do this, and think about whether I care.

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ANU hiring postdocs
*November 19, 2014*

*Posted by Scott Morrison in Uncategorized.*

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Amnon Neeman has just put up an ad for two postdoctoral positions at the ANU. He says: “The successful applicants should have strong research interests and activities in or related to one of the following fields: Algebraic Geometry, Commutative Algebra, Representation Theory, Algebraic Topology, Algebraic K-Theory. Skills at applying the techniques of triangulated categories to these areas would be a plus.”

These are excellent positions — available for up to 3 years, with no teaching requirements, and salaries in the AUD81-89k range.

Applications close at the end of January, and I hear Amnon is keen to hire as soon as possible.

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Grothendieck 1928-2014
*November 13, 2014*

*Posted by Scott Morrison in Uncategorized.*

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Editorial board of “Journal of K-Theory” on strike, demanding Tony Bak hands over the journal to the K-Theory foundation.
*September 14, 2014*

*Posted by Scott Morrison in Uncategorized.*

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Text of the announcement below:

Dear Colleagues,We the undersigned announce that, as of today 15 September 2014, we’re starting an indefinite strike. We will decline all papers submitted to us at the Journal of K-Theory.Our demand is that, as promised in 2007-08, Bak’s family company (ISOPP) hand over the ownership of the journal to the K-Theory Foundation (KTF). The handover must be unconditional, free of charge and cover all the back issues.The remaining editors are cordially invited to join us.Yours Sincerely,Paul Balmer, Spencer Bloch, Gunnar Carlsson, Guillermo Cortinas, Eric Friedlander, Max Karoubi, Gennadi Kasparov, Alexander Merkurjev, Amnon Neeman, Jonathan Rosenberg, Marco Schlichting, Andrei Suslin, Vladimir Voevodsky, Charles Weibel, Guoliang Yu

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The many principles of conservation of number
*March 4, 2014*

*Posted by David Speyer in Uncategorized.*

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In algebraic geometry, we like to make statements like: “two conics meet at points”, “a degree four plane curve has bitangents”, “given four lines in three space, there are lines that meet all of them”. In each of these, we are saying that, as some parameter (the conics, the degree four curve, the lines) changes, the number of solutions to some equation stays constant. The “principle of conservation of number” refers to various theorems which make this precise.

In my experience, students in algebraic geometry tend to pick up the rough idea but remain hazy on the details, most likely because there are many different ways to make these details precise. I decided to try and write down all the basic results I could think of along these lines.

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Mathematical Research Community on Cluster Algebras in Utah this summer
*February 26, 2014*

*Posted by David Speyer in Uncategorized.*

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This June 8 to 14, there will be a week long gathering in Snowbird, Utah for young mathematicians working on cluster algebras. The target audience here are either current graduate students, or people with Ph. D. in the last 3 or so years, who would be ready to start working on problems in cluster algebras. The hope is to spend a lot of time getting collaborations and projects going during the week. The organizers are Michael Gekhtman, Mark Gross, Gregg Musiker, Gordana Todorov and me.

We still have room for a number more applicants, so we would like to encourage more of you to apply. Please note that the application deadline of March 1 is firm.

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Australian Research Council journal list
*February 24, 2014*

*Posted by Scott Morrison in Uncategorized.*

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(This post may only be of interest to Australian mathematicians; sorry!)

Summary:A number of mathematics journals (e.g. Quantum Topology, Forum of Mathematics Sigma and Pi, and probably many others), are not listed on the new official journal list in Australia. Please, help identify missing journals, and submit feedback via http://jacci.arc.gov.au/.

Every few years the Australian Research Council updates their “official list of journals”. One might wonder why it’s necessary to have such a list, but nevertheless it is there, and it is important that it is accurate because the research outputs of Australian mathematicians are essentially filtered by this list for various purposes.

There is a new draft list out, and the purpose of this post is to coordinate finding missing journals, and to ensure that interested mathematicians submit feedback before the deadline of March 15. Please note that while in the past this list included dubious rankings of journals, the current list is just meant to track all peer reviewed journals in each subject. Having a journal missing entirely means that some published papers will not be counted in measures of a department’s or university’s research output.

You can access the full list here, just journals marked as mathematics here, and just the journals marked a pure mathematics here. These are not the “official” lists, which you have to create an account (follow the instructions at http://www.arc.gov.au/era/current_consult.htm) to view, and even then only an Excel version is available. I hope that by making these mathematics specific lists available in a standard format, more mathematicians will take the time to look over the list.

Please look through the lists. If you see something missing, please comment here so we all know about it. In any case, please submit feedback via http://jacci.arc.gov.au/ (you’ll have to create an account first) recommending inclusion of the journals identified so far. Submitting a missing journal requires identifying an article published in it by an Australia author; feel free to add this information here as well if appropriate. (Thanks to Anthony Henderson for pointing out this detail!)

It is also possible to submit additional “FoR” (field of research) codes for journals on the list, and this may be of interest to people publishing cross-disciplinary research. Feel free to make suggestions along these line here too: the AustMS has been advised that “multiple responses, rather than a single AustMS one, will carry more weight on this aspect”.

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Mathematics Literature Project progress
*January 6, 2014*

*Posted by Scott Morrison in Uncategorized.*

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We’ve made some good progress over at the Mathematics Literature Project. In particular, we’ve completely analyzed the 2013 issues of five journals:

(The colour coded bars show the fractions of papers available on the arXiv, available on authors’ webpages, and not freely accessible at all; these now appear all over the wiki, but unfortunately don’t update automatically. Over at the wiki you can hover over these bars to get the numerical totals, too.)

Thanks everyone for your contributions so far! If you’ve just arrived, check out the tutorial I made on editing the wiki. Now, it’s time to do a little planning.

### What questions should we be asking?

Here’s one we can start to answer right away.

What fraction of recent papers are available on the arXiv or on authors webpages?For good generalist journals (e.g. Adv. Math. and Annals), almost everything! For subject area journals, there is wide variation (probably mostly depending on traditions in subfields): AGT is almost completely freely accessible, while Discrete Math. is at most half.

I hope we’ll soon be able to say this for many other journals, too.

Here’s the question I really want to have answers for:

Does being freely accessible correlate well with quality?It’s certainly tempting to think so, seeing how accessible Advances and Annals are. I think to really answer this question we’re going to have to classify all the articles in slightly older issues (2010?) and then start looking at the citation counts for articles in the two pools. If we get coverage of more journals, we can also look for the correlation between, say, impact factor and the ratio of freely accessible content.

### What next?

I don’t want to just list every journal on the wiki; it’s best if editors (and the helpful bots working in the background) can focus attention and enjoy the pleasures of finishing off issues and journals. Suggestions for journals to add next welcome in the comments. I’ve already included the tables of contents for the Journal of Number Theory, and the Journal of Functional Analysis. (It will be nice to be able to make comparisons between JFA and GAFA, I think.)

I’ve been working with some people on automating the entry of data in the wiki (mainly by using arXiv metadata; there are actually way more articles there with journal references and DOIs than I’d expected). Hopefully this will make the wiki editing experience more fun, as a lot of the work will have already been done, and humans just get to handle the hard and interesting cases.