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Gershom B
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Category theory in context

+Emily Riehl 's (second) book is published!

You can get the free pdf copy from Emily's website [1] but the paper copy is only about $30 (US, I guess). It's a decent 272 pages long, slightly more than my copy of Categories for the working mathematician, so you may wish to have it on your shelf as well.


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Google groups? No longer properly searchable. Google news archive? Gone. Google books? Still there so far but with content addition apparently frozen. So where else can we go to find the research tools that we need? Much of the article focuses on the Internet Archive, which is indeed a wonderful resource, but only covers some of these types of content.

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Publons to the max

Not some bad science fiction from the 1970s, but the fact I've decided I want to make all my referee reports open on Publons [1]. I've already been signing my referee reports now for a few years [2], so I just emailed all the people whose papers I've refereed to let them have a veto on me making the reports public. My hope is that they won't have any objections, since I can only make reports on published papers public (and so these are all papers I've recommended for publication) and I like to give very constructive suggestions wherever I feel something is lacking.

There are apparently some issues with certain publishers disallowing the public access to referee reports, but if the author(s) of the paper agree and the reviewer agrees, then it can only be a good thing, in my view. At the very least, I'll get feedback on whether people think my style of refereeing is good or otherwise, and also be a useful example to others (apparently, according to Publon statistics, I write reviews rather longer than average).



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In three highly regarded journals, Annals of Mathematics, Inventiones Mathematicae, and Journal of the AMS, a significant underrepresentation of women persists without notable uptrend over the last four decades. While the presence of women is shown to strongly fluctuate across mathematical fields, the choice of research fields is found not to be responsible for the substantial underrepresentation of women in said three journals.


A negative correlation exists between journal rank, measured using the ERA ranking or the journal impact factor, and the percentage of women among its authors, a pattern that remains fairly stable over time.

This kind of systematic bias deserves to be shouted from the rooftops.

EDIT: I should add that this data could be even more strongly supported if people comb through eg MathSciNet for the named journals (or the journals themselves!) to see if the algorithmic detection used in the article was accurate. END EDIT


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New open-access electronic journal on higher category theory! (And with a very nice looking editorial board)

Higher Structures is an all-electronic, refereed journal on the theory of higher structures and its applications in the mathematical sciences.

This journal publishes articles that make significant new contributions to mathematical science using higher structures, or that significantly advance our understanding of the foundational aspects of the theory of such structures. The scope of the journal includes: higher categories, operads and their generalisations, and applications of these to Algebra, Geometry, Topology, Combinatorics, Logic and Mathematical Physics.

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_Quantum Theory, Groups and Representations:
An Introduction_

This book by Peter Woit (discussed here: ) seems like a very nice, readable, introduction to quantum theory from a group-theoretic standpoint.

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I did not know Kristoffer Rose very well, but nonetheless I am very sorry to hear of his death. I first met him by chance at a debian-related NY holiday event, where I didn't think I would run into more researchy folks. He had just started at two sigma and we had a wonderful, wide-ranging conversation on his past work on term rewriting and compilers at IBM Watson, and his aspirations for bringing that into more practical industrial settings. His explanations to me of his conception of term-rewriting stuck with me over the years and opened my eyes to a range of research I had not paid much attention to prior. And Kris himself was quite involved there -- serving on the program committee of Rewriting and Term Analysis, and also as I understand it helping found the workshop on Higher Order Rewriting.

Researchers hope to remembered by their work and live on in its impact. So let me share a few things that Kristoffer worked on:

One achievement he spoke of that he considered a career high-point was building a compiler pipeline composed purely of higher-order rewriting passes, thus demonstrating the unifying power of this formalism:

And only now have I found that his thesis was on optimal reduction models for the lambda calculus, something that many of us have an affection for:

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This required corporate training is not the introduction to that I was hoping for...

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This is a great talk. Haven't read the paper yet, but looking forward to it.
It took me four years to write the paper "Five stages of accepting constructive mathematics", which is based on an eponymous talk I gave at the Institute for Advanced Study in 2013. The paper has been published in the Bulleting of the AMS. I hope you'll enjoy it! 

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Lew Gordeev, Edward Hermann Haeusler

(Submitted on 30 Sep 2016)

We present a proof of the conjecture NP = PSPACE by showing that arbitrary tautologies of Johansson's minimal propositional logic admit "small" polynomial-size dag-like natural deductions in Prawitz's system for minimal propositional logic. These "small" deductions arise from standard "large"\ tree-like inputs by horizontal dag-like compression that is obtained by merging distinct nodes labeled with identical formulas occurring in horizontal sections of deductions involved.
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