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White House Launches New Campaign to Foster Interest in Math and Science

 On Monday the White House launched "Educate to Innovate," a new campaign which enlists companies and nonprofit groups in an effort to encourage students to pursue careers in math, science, technology, and engineering.

Hundreds Line up at University of Utah's Science Day

"It's a record-breaking crowd. We've never had this many students," claimed Brian Saam, associate dean of the College of Science.  Saam was referring to the more than 900 high school students, from 150 schools out West, who woke up early on November 7, 2009, to attend Science Day at the University of Utah, in Salt Lake City.

The Formula for the Perfect Free-Throw

Improving your free-throw percentage is a simple matter of mathematics, according to researchers Drs. Chau Tran and Larry Silverberg of North Carolina State University.

Steven G. Krantz Appointed Editor of Notices of the AMS

Steven G. Krantz (Washington University in St. Louis) will be the next editor of Notices of the American Mathematical Society starting with the January 2010 issue. He succeeds Andy Magid (Ohio University), who has been editor since January 2004.

MathDL Loci Featured Items RSS feed

A Gallery of Ray Tracing for Geometers

From: Loci

New This gallery of images and animations shows many examples of how the POVray ray-tracing software can be used to display examples in three-dimensional geometry,

Trisecting a Line Segment (With World Record Efficiency!)

From: Loci

New This article looks at several geometric, straightedge-and-compass constructions for trisecting a line segment, comparing them based on the numbers of lines or circles required for the construction.

Thinking Outside the Box -- or Maybe Just About the Box

From: Loci

This article presents a fresh look at an age-old calculus optimization problem, the 'box problem.' (Also includes a Student Module condensed from the article.)

More Features:

From: Loci

• Seashells
• Visualizing Lie Subalgebras
• Math on the Web Made Easier
• Generalized Baseball Curves

MAA Book Reviews - Read This!

The Moore Method: A Pathway to Learner-Centered Instruction

The Moore Method: A Pathway to Learner-Centered Instruction

A Guide to Real Variables

A Guide to Real Variables

Mind and Nature: Selected Writings on Philosophy, Mathematics, and Physics

Mind and Nature: Selected Writings on Philosophy, Mathematics, and Physics

Visual Group Theory

Visual Group Theory

math updates on arXiv.org

Noncommutative Figa-Talamanca-Herz algebras for Schur multipliers. (arXiv:0911.4304v1 [math.OA])

Authors: Cédric Arhancet

We introduce a noncommutative analogue of the Fig\'a-Talamanca-Herz algebra $A_p(G)$ on the natural predual of the operator space $\frak{M}_{p,cb}$ of completely bounded Schur multipliers on Schatten space $S_p$. We determine the isometric Schur multipliers and prove that the space $\frak{M}_{p}$ of bounded Schur multipliers on Schatten space $S_p$ is the closure in the weak operator topology of the span of the isometric multipliers.

Automorphisms of Chevalley groups of type $B_l$ over local rings with 1/2. (arXiv:0911.4243v1 [math.GR])

Authors: Elena I. Bunina

In the given paper we prove that every automorphism of a Chevalley group of type $B_l$, $l\geqslant 2$, over a commutative local ring with 1/2 is standard, i. e., it is a composition of ring, inner and central automorphisms.

Unitarization of linear representations of non-primitive posets. (arXiv:0911.4237v1 [math.RT])

Authors: Roman Grushevoi, Kostyantyn Yusenko

We prove that partially ordered set has finite number of finite-dimensional indecomposable nonequivalent Hilbert representations with orthoscalarity condition if and anly if it has finite number of indecomposable linear representations. We show that each indecomposable representation of the poset of finite type could be unitarized with some weight.

Surface links with free abelian link groups. (arXiv:0911.4235v1 [math.GT])

Authors: Inasa Nakamura

It is known that if a classical link group is a free abelian group, then its rank is at most two, and a $\mu$-component 2-link group for $\mu>1$ is not a free abelian group. In this paper we give examples of surface links whose link groups are free abelian groups of rank three or four. Moreover we show that the examples of rank three are infinitely many and one of them has the triple point number four.

Quasi-morphisms on Free Groups. (arXiv:0911.4234v2 [math.GR])

Authors: Pascal Rolli

Let F be the free group over a set of two or more generators. R. Brooks constructed an infinite family of quasi-morphisms on F such that an infinite subfamily gives rise to independent classes in the second bounded cohomology of F, which proves that this space is infinite dimensional. We give a simpler proof of this fact using a different type of quasi-morphisms. After computing the Gromov norm of the corresponding bounded classes, we generalize our example to obtain quasi-morphisms on free products, as well as quasi-morphisms into groups without small subgroups, also known as epsilon-representations.

Optimal control of a large dam, taking into account the water costs [New Edition]. (arXiv:0911.4228v1 [math.PR])

Authors: Vyacheslav M. Abramov

This paper studies large dam models where the difference between lower and upper levels $L$ is assumed to be large. Passage across the levels leads to damage, and the damage costs of crossing the lower or upper level are proportional to the large parameter $L$. Input stream of water is described by compound Poisson process, and the water cost depends upon current level of water in the dam. The aim of the paper is to choose the parameters of output stream (specifically defined in the paper) minimizing the long-run expenses. The particular problem, where input stream is Poisson and water costs are not taken into account has been studied in [Abramov, \emph{J. Appl. Prob.}, 44 (2007), 249-258]. The present paper partially answers the question \textit{How does the structure of water costs affect the optimal solution?} In particular the case of linear costs is studied.

A new approximation of relaxed energies for harmonic maps and the Faddeev model. (arXiv:0911.4224v1 [math.AP])

Authors: Mariano Giaquinta, Min-Chun Hong, Hao Yin

We propose a new approximation for the relaxed energy $E$ of the Dirichlet energy and prove that the minimizers of the approximating functionals converge to a minimizer $u$ of the relaxed energy, and that $u$ is partially regular without using the concept of Cartesian currents. We also use the same approximation method to study the variational problem of the relaxed energy for the Faddeev model and prove the existence of minimizers for the relaxed energy $\tilde{E}_F$ in the class of maps with Hopf degree $\pm 1$.

Message Passing Algorithms for Compressed Sensing: II. Analysis and Validation. (arXiv:0911.4222v1 [cs.IT])

Authors: David L. Donoho, Arian Maleki, Andrea Montanari

In a recent paper, the authors proposed a new class of low-complexity iterative thresholding algorithms for reconstructing sparse signals from a small set of linear measurements \cite{DMM}. The new algorithms are broadly referred to as AMP, for approximate message passing. This is the second of two conference papers describing the derivation of these algorithms, connection with related literature, extensions of original framework, and new empirical evidence.

This paper describes the state evolution formalism for analyzing these algorithms, and some of the conclusions that can be drawn from this formalism. We carried out extensive numerical simulations to confirm these predictions. We present here a few representative results.

ScienceDaily: Mathematics News

Visual assistance for cosmic blind spots

Information field theory enables astronomers, medical practitioners and geologists to look into places where their measuring instruments are blind.

Cause behind the characteristic shape of a long leaf revealed

Applied mathematicians dissected the morphology of the plantain lily, a characteristic long leaf with a saddle-like arc midsection and closely packed ripples along the edges. The simple cause of the lily's fan-like shape -- elastic relaxation resulting from bending during differential growth -- was revealed by using an equally simple technique, stretching foam ribbons.

Active hearing process in mosquitoes

A mathematical model has explained some of the remarkable features of mosquito hearing. In particular, the male can hear the faintest beats of the female's wings and yet is not deafened by loud noises.

Examining mathematical abilities in children with fetal alcohol spectrum disorder

Children with fetal alcohol spectrum disorder (FASD) have a number of cognitive deficits. Mathematical ability seems particularly damaged in children with FASD. A new study supports the importance of the left parietal area for mathematical abilities in children with FASD.

Immediate, aggressive spending on HIV/AIDS could end epidemic

Money available to treat HIV/AIDS is sufficient to end the epidemic globally, but only if we act immediately to control the spread of the disease, according to new research. This approach defies conventional thinking, which recommends gradual spending over 15-20 years. The study was based on a mathematical model developed by mathematicians and biologists, who recently earned acclaim for a study on how best to handle a planetary invasion by zombies.

Facial biometrics system capable of creating a facial 'DNA'

Research into techniques of facial biometrics, carried out by scientists in Spain, has resulted in a system that is able to recognize the facial "DNA" of every individual by determining his/her most noteworthy facial traits, with a of 95% rate of precision.

Underground Power Lines That Bypass Monuments In Cities

Mathematicians have created a method to design underground lines whereby a city's historical buildings are unaffected.

When Is A Fetus Able To Survive Outside The Womb?

Mathematicians are coupling mathematical models with information about a baby's physiology inside the womb. Combining ultrasound with powerful algorithms based on real-life data, pediatricians get critical data on the development of the fetal circulatory system, so they can determine when the baby is strong enough to survive on its own.