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Alex Nelson
Works at Unfold, Inc.
Attended University of California, Davis
Lives in Los Angeles, California
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Alex Nelson

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Further light reading...

http://arxiv.org/abs/1508.06720
Abstract: We prove the folklore corollary of the geometrization theorem that there is an algorithm for the homeomorphism problem for closed, oriented, triangulated 3-manifolds. To support the interpretation of this result as a corollary of geometrization, we give a self-contained proof that uses ...
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If you have a sailor mouth, and need to reform your profane vocabulary, then --- By the double-barrelled jumping jiminetty! --- these might be for you: http://mentalfloss.com/article/49652/10-old-fashioned-swears-spice-your-cussin
Taboos against what we would consider pretty mild exclamations led swearers of years past to come up with creative substitutions, and they've left their mark on our vocabulary.
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I was recently at Davis, wandering around for a couple days with a friend who also studied there. They have a great used bookstore, with a rich math and science section (in fairness, they have a great history and classics sections, too).

Someone apparently ditched a number of statistical mechanics texts there, which they were selling for a song. Raymond Streater (of PCT, Spin and Statistics, and All That fame) wrote a great book Statistical Mechanics which starts from rudimentary probability, and works its way up to quite in-depth statistical mechanics.

I may start working my way through it, and several other Stat-mech texts, attempting to collate some notes on the subject...but Streater's book really is quite good at filling that niche for probability theorists, I think.

https://localwiki.org/davis/Logos_Books
Location. 513 2nd Street. Hours. Tuesdays through Saturdays, 10am to 8 pm. Sundays, 10 am to 6 pm. Closed Mondays. Phone. (530) 400-1083. Website. http://logosbooks.wordpress.com/ for updates on upcoming events. Email. logosusedbooks@gmail.com. Owners. Susan and Peter Linz. Opening Day ...
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I know Streater, but not that particular book of his! Sounds like a good bookstore.
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Alex Nelson

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Predicting Baseball Game Outcomes

"It's tough to make predictions, especially about the future."
— Yogi Bera, Apocryphal

If you're following me on twitter (h/t to you,@moneySpamBot2123!) or have been glancing at my periodic predictions here on G+, you'll notice that most of the time I'm so darn wrong.

But occasionally, I'm on the money. What's up with that?

Well, after much examination of the matter, it appears that the problem boils down to not accounting for the pitcher's abilities. Overall, in a batter-pitcher interaction, roughly 40% of the outcome is determined by the pitcher. (Alright, well, 39.78%, but who's counting?)

So if we have a bad pitcher (e.g., Ervin Sanatana for the Minnesota Twins returning after being banned for 80 games), then the outcome will not resemble the prediction at all (FWIW, I predicted it would be Twins 5 vs Cincinnati 4 --- it turned out to be 4-17...I was close!).

I'm still thinking about how to adequately represent this, because a naive Markov chain won't do anymore. The random variation in the pitcher's ability is a real effect (as I study in this post). I'm going to have to sit down, and think carefully about how to model these interactions.

The other low-hanging fruit was determining the lineup. But this turns out to be fairly easy to predict, since it doesn't change too much game-to-game.

http://pqnelson.github.io/2015/08/17/lineups-and-pitchers.html
Lineups and Pitchers, Observations on Markov Chains. by Alex Nelson, 17 August 2015. Executive Summary. We discuss the impact of the lineup and pitcher on predicting game outcomes. Contents. Lineup Matters. Determining the Lineup. Predictions. Cleveland Indians vs Anaheim Angels (August 3, 2015) ...
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More light reading http://arxiv.org/abs/1508.01810
Abstract: The constraint equations for smooth $[n+1]$-dimensional (with $n\geq 3$) Riemannian or Lorentzian spaces satisfying the Einstein field equations are considered. It is shown, regardless of the signature of the primary space, that the constraints can be put into the form of an ...
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Abstract: There is good evidence that full general relativity is non-integrable or even chaotic. We point out the severe repercussions: differentiable Dirac observables and a reduced phase space do not exist in non-integrable constrained systems and are thus unlikely to occur in a generic ...
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Alex Nelson

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Puzzle (Weinberg). Given a map of Middle Earth, and from the distances between each pair of these 4 cities (Hobbiton, Erobor, Dagoriad, and the City of the Corsairs), determine:

(a) is Middle Earth flat?

(b) If it is a sphere, what is the radius of Middle-Earth?


Addendum. After examining the web for these distances, I found the best approximations to be:

from Hobbiton to Erebor: 750 miles
from Hobbiton to Dagorlad: 890 miles
from Hobbiton to The City of the Corsairs: 1250 miles
from Erebor to Dagorlad: 595 miles
from Erebor to The City of the Corsairs: 1295 miles
from Dagorlad to The City of the Corsairs: 700 miles

(Weinberg gave different distances in his puzzle.)
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Abstract: We believe, in the sense of supporting ideas and considering them correct while dismissing doubts about them. We take sides about ideas and theories as if that was the right thing to do. And yet, from a rational point of view, this type of support and belief is not justifiable at all.
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In a recent essay in New York Magazine, Molly Fischer wrote that David Foster Wallace has become a hero of “bros,” which “drives some women to treat “loves DFW” as synonymous with “is one of those ...
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A complete guide to the hotter, higher, trashier, fish-free oceans of the near future.
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Have him in circles
811 people
Arpit Tripathi's profile photo
Markus Översti's profile photo
David Foster's profile photo
Michael Hilding's profile photo
Cinema's profile photo
mukesh saini's profile photo
Sun Lit Energy's profile photo
Cliff Harvey's profile photo
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Education
  • University of California, Davis
    Mathematics, 2006 - 2011
Basic Information
Gender
Male
Other names
Alexander Nelson
Story
Tagline
They call me "Tractor Man"
Introduction
I'm a mathematical physicist (more on the mathematical side) with interests in category theory, monstrous moonshine, number theory, Diophantine approximations, super symmetry, Lie groups, differential geometry, and other topics. On the physical side, I'm intrigued by quantization of gauge systems, Quantum Field Theory, the mathematical underpinnings of particle physics, classical and quantum gravity.

I've been to Nottingham, England in July 2008 to attend Quantum Gravity and Quantum Geometry 2; and I've attended "Algebra and Topology in Interaction" during September 2009, in honour of Dr Fuchs' Birthday.

Starting June 2009 until June 2010, I did undergraduate research with Derek Wise with funding from VIGRE. We worked on Chain Field Theory in discrete spacetimes.

In April 2010 I was asked to peer review for the International Journal of Physical Sciences.

August 2010 I studied abroad at Trinity in Dublin, and Queen's University in Belfast.

In June 2011, I attended "Quantum Geometry and Quantum Gravity" in Zurich, Switzerland; then in July I went to the "Category Theory 2011" conference in Vancouver.

February 2012, I attended "
30th Annual Western States Mathematical Physics Meeting" at Caltech.
Bragging rights
Hardest working man in show business.
Work
Occupation
Mathematician/Programmer/Oracle
Employment
  • Unfold, Inc.
    Software Developer, 2012 - present
    I program in Clojure (Lisp for JVM), do numerical analysis, predict how congress will vote, analyze the Syrian Civil War, and much much more!
  • University of California, Davis
    Student, Researcher, 2006 - 2011
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
Los Angeles, California
Previously
Davis, California - Glendale, California - Dublin, Ireland - Belfast, Northern Ireland - Padua, Italy
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