Solving an expected value problem without using geometric series

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**Irene Stegun, the Handbook of Mathematical Functions, and the Lingering Influence of the New Deal**

by David Alan Grier

grier@gwu.edu

*The Handbook of Mathematical Functions* is one of the most widely circulated mathematical references. It is also one of the few large, collaborative mathematical projects and a rare example of a twentieth-century mathematical activity led by a woman. The effort that prepared the *Handbook* had its origins in the relief office of the New Deal, the Mathematical Tables Project of the Work Projects Administration. This office, which was organized to provide jobs for the unemployed, offered an unusual opportunity for mathematically inclined women and trained many of the contributors to the handbook.

**Noncrossing Partitions in Surprising Locations**

by Jon McCammond

jon.mccammon@math.ucsb.edu

Certain mathematical structures make a habit of reoccurring in the most diverse list of settings. Some obvious examples exhibiting this intrusive type of behavior include the Fibonacci numbers, the Catalan numbers, the quaternions, and the modular group. In this article, the focus is on a lesser known example: the noncrossing partition lattice. The focus of the article is a gentle introduction to the lattice itself in three of its many guises: as a way to encode parking functions, as a key part of the foundations of noncommutative probability, and as a building block for a contractible space acted on by a braid group. Since this article is aimed primarily at nonspecialists, each area is briefly introduced along the way.

**Linear Independence and Series Expansions in Function Spaces**

Ole Christensen and Khadija Laghrida Christensen

Ole.Christensen@mat.dtu.dk

We consider complex vector spaces generated by certain special functions and examine whether their linear combinations have unique representations. We consider trigonometric functions, complex exponential functions, and certain more complicated systems of functions (Gabor systems and wavelet systems) that have recently attracted much attention both in pure mathematics and in applied science. We present some open problems related to those systems, problems that are easy to formulate but apparently very difficult to solve. Finally, we introduce frames, which generalize the concept of an orthonormal basis. The motivation for this generalization comes from Gabor analysis, where we show that certain desirable properties are incompatible with the orthonormal basis requirement. We show how the concept of linear dependence for wavelet systems plays a key role in modern constructions of frames having wavelet structure.

**Rearranging the Calculus Sequence to Better Serve Its Partner Disciplines**

Bernd S. W. Schröder

schroder@coes.LaTech.edu

This paper shows how the calculus-differential equations sequence for disciplines close to mathematics can be rearranged in a multitude of ways to better serve our partner disciplines. One possible rearrangement is described in the context of a college wide effort to reintegrate engineering, mathematics, and the sciences.

**Notes**

**A Geometric Proof That e is Irrational and a New Measure of Its Irrationality**

by Jonathan Sondow

jsondow@alumni.princeton.edu

**Pairings and Signed Permutations**

by Valerio De Angelis

vdeangel@xula.edu

**Iterated Products of Projections in Hilbert Space**

by Anupan Netyanun and Donald C. Solmon

an0079@unt.edu, solmon@math.oregonstate.edu

**Noting the Difference: Musical Scales and Permutations**

by Danielle Silverman and Jim Wiseman

danielle.silverman@alum.swarthmore.edu, jwisema1@swarthmore.edu

**On a Congruence modulo a Prime**

by Hao Pan

haopan79@yahoo.com.cn

**Problems and Solutions**

**Reviews**

*When Computers Were Human*

by David Alan Grier

Reviewed by David E. Zitarelli

david.zitarelli@temple.edu