Welcome!

This is the personal website of Armin Straub.

Currently, I'm studying mathematics at Tulane University, New Orleans. My PhD advisor is Victor H. Moll, and my research area is an exciting mix of combinatorics, special functions and computer algebra.

This website is about to replace my old one.

Date: Aug 16, 2010

A gentle introduction to PSLQ

PSLQ is an algorithm to find integer relations between a set of real numbers. Last summer I had written an introduction to PSLQ, how it works, and how it can and has been used. This introduction, which can be downloaded below, should be easily understandable by an advanced undergraduate student.

The PSLQ algorithm is one of the basic tools of experimental mathematics. A very basic and naive implementation for Mathematica is attached to this post. The file pslq-usage.nb contains instructions and examples. read more »

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pslq.pdf
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pslq.m
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pslq-usage.nb
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Date: Aug 2, 2010

FPSAC 2010

I'm currently happy attendant of FPSAC 2010 (formal power series & algebraic combinatorics) in San Francisco. My talk on random walks in the plane has been the very first regular one, which means that I can now fully enjoy all the other ones. read more »

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randomwalks-fpsac2010.pdf
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Date: Jul 29, 2010

Reading mathematical papers on the Nook

Recently, I got myself a Nook because it seems perfect for reading while traveling when you (literally, with the current baggage restrictions) can't afford to have several rather voluminous books with you. While hoping that this Nook will lower hurdles for picking up some non-mathematical reading again, another big hope was that I would be able to read mathematical papers (and possibly books) on it so as to spare the rain forest and me. read more »

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cenbin-nook.pdf
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ramanujantau-nook.pdf
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Date: Jul 23, 2010

KDE clipboard on the command line

The attached python script clip.py makes it easy to use the KDE clipboard on the command line. read more »

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clip.py.gz
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clip3.py.gz
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Date: Jul 8, 2010

The "What Is...?" column

I very much enjoy reading the "What Is…?" column in the Notices of the AMS. Unfortunately, there seemed to be no index to this column. I have therefore created this one in the hope that it'll be helpful to others as well.

  1. What is…an amoeba? — Oleg Viro, September 2002
  2. What is…the monster? — Richard Borcherds, October 2002
read more »
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Date: Mar 5, 2010

Computer proved monotonicity of some coefficients

Ming-Hua Lin from the University of Regina sent me the following problem:

Problem: Let p ≥ 2 be an integer, and define

$$ f (t) = \left( \frac{1}{1 - t \left( \frac{1}{p} + \frac{p - 1}{2 p^2} t<br /> \right)} \right)^p = \sum_{n \geqslant 0} c_n t^n . $$

Show that $ c_2 > c_3 > c_4 > \cdots $. read more »

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Date: Aug 18, 2009

CARMA workshop in Newcastle, 2009

On August 18, 2009, the University of Newcastle hosted a CARMA workshop on Multidimensional Numerical Integration and Special Function Evaluation. Besides enjoying very interesting talks it's been my pleasure to present, together with James Wan, on progress of our joint work with Jon Borwein, Peter Donovan and Dirk Nuyens on expectations of random walks. read more »

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randomwalkintegrals.pdf
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Date: Jun 12, 2009

Apollonian circle packings in Mathematica

Today, I have been playing a little bit with Apollonian circle packings. Here is the code I wrote in Mathematica to visualize such packings (see below for an example). read more »

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apolloniancirclepackings.nb
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Date: Jun 10, 2009

Fast q-binomials in Mathematica

Recently, I have been doing experiments involving q-binomial coefficients in Mathematica. Starting with version 7, Mathematica is prepared for some q-business; in particular, there exists a function named QBinomial giving the q-analog of Binomial. However, this implementation turned out to not be fast enough for my needs. Here is an alternative approach which is not only way faster but provides a full factorization. read more »

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