#mathoverflow

[liskantope]

I’m not going to look back at my post from a year ago outlining what I hoped to accomplish in 2018 blogging-wise, because this year didn’t go great for me in that way and I know I fell way short of most of those goals. While I’m happy with my Tumblr activity (I felt more engaged than ever and if anything exceeded the number of posts I expected to write), I came nowhere near managing my intended 12 Wordpress posts for the year (and some of the ones I made were partly reprints of things I’d written 10 or 12 years ago), nor did I succeed in getting into the groove of doing high-quality-yet-low-energy-spontaneous writing there. Even worse, I had really hoped to immerse myself better in the Less Wrong (2.0) community but almost completely failed to do that. For at least a couple of months, I did keep a tab open on my browser and kept up with many of their frontpage posts until somehow I fell out of the habit -- this is very similar to my attempts to become more active on MathOverflow -- and I made well-received comments on a few other people’s posts. But I got nowhere near the exchange of ideas I hoped to enter there.

At least three reasons for this disappointing result are obvious: (1) I traveled more than in most calendar years, at least in the second half; (2) I’ve had much more work-related stress than usual in the last few months due to having reentered the job market; and (3) a couple of what I felt were big, bright ideas that would come together properly if I tried to put them into writing totally fell apart. (The latter issue is largely responsible for me not feeling that motivated to contribute to Less Wrong.)

I’m not going to make those things goals for 2019, since I don’t see (1)-(3) above not applying this year. Maybe I’ll do a little less traveling, but I’m almost certainly going to be moving countries this year, and that plus the continued job search alone is likely to make things quite disruptive for me.

Anyway, contributing such-and-such number of essays to this or that blog or community should never be the primary objective. I’m just going to look forward to another year of hanging out in these spaces, discoursing whenever something interesting is being discoursed and when I have time, and further getting to know everyone.

[waybackwanderer]

User Cleo - MathOverflow Jul 2016 Archived Web Page 🎃

[stackexplorer]

“Can you give examples of proofs without words? In particular, can you give examples of proofs without words for non-trivial results?”

A bit on the technical side, but interesting nonetheless.

[eka-mark]

I like to say that there is only a single abstract definition of cohomology: in any (∞,1)-topos H given objects X and A, the cohomology of X with coefficients in A is the connected components of the hom-∞-groupoid H(X,A) := π₀H(X,A). Everything else one sees described as "cohomology" is, i claim, a special case and a special realization of this situation.

Urs Schreiber, MathOverflow answer (x)

[mathkonspekt]

This question is connected with my previous: Heisenberg group: function without vertical derivative. Here I am trying to look from another side: what is a difference between Sobolev space and hori...

[eka-mark]

A nice thing about the usual formulation of [the Univalence Axiom] in the form (A=B)≃(A≃B) is that it implies (A=B)=(A≃B), by UA one universe up.

Steve Awodey on MathOverflow (x)

[eka-mark]

Nowdays the refereeing process is so hasty, erratic and nobody has time for it, that the acceptance is more and more often based on the general impression of the results (combined with the authority expectations) rather than on strict checking of proofs. This is unfortunate and makes arxiv very little different from "published" journals. A colleague of mine said "Why would some referee tell me which paper to read ? I look at a paper on arXiv myself and decide myself if I find it worthy to read."

Zoran Skoda, MathOverflow comment (x)

[dataanxiety]

Internet esoterica

This is an exceptional image. Allow me to give some words of warning: It would be better not to inspect the source any further.

Ngecrit, bro. pic.twitter.com/vRnkLsdMdj

— helda (@frauassenava)

October 2, 2013

I happened upon it by coincidence, a mere three hop's distance from Math Overflow.

Hop 1 and Hop 2

I am a mathematician; next term I'll teach "The Magic of Numbers''. Now in math the magic is not in special numbers, but in the fabric of number systems, the wonderful relations that tie numbers together. But in the Book of Revelations...a number is credited with special powers. 666 hardly occurs elsewhere in Scripture. The Revelation text draws particular attention to that number-- hinting at some secret, the hidden ID number of the Devil that would unmask him, if only we knew where and how to look.

Over the centuries people have found the dreaded number everywhere from the Pope to pop culture, from Roman numerals to Viagra. That's right: Viagra has a molecular weight of 666. Just a few months ago, devout moviegoers in Georgia were spooked when their tickets for Mel Gibson's The Passion of the Christ had serial numbers that began with three sixes. As for Roman numerals, add up I, V, X, etc.: one and five, ten and fifty, a hundred and five hundred -- you do the math.

He cited an oddly named dictionary, a Gematria, with URL. I navigated into the breach. Go back a few centuries, to the early Enlightenment, to 16th century Mittel-Europa. That's what I did, in a web sort of way.

Hop 3

The next website (which was not affiliated with Harvard University, nor my Jewish mathematician!) had many sub-directories, many paths. One led me to this startling page. EDIT: Since gone 404. Try this http://www.esotericarchives.com The subject matter is genuinely esoteric. The fact that there were no fewer than 57 people actively conversing there, on IRC, was equally remarkable. From there, I found the surreal image above, as well as many much more disturbing ones in the same user's timeline.

I'll stop now. Enjoy the cool image. Take my advice. Do NOT look for sights that cannot be unseen.