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Full-Text Articles in Physical Sciences and Mathematics

Combinatorial Proofs Of Fibonomial Identities, Arthur Benjamin, Elizabeth Reiland Dec 2014

Combinatorial Proofs Of Fibonomial Identities, Arthur Benjamin, Elizabeth Reiland

All HMC Faculty Publications and Research

We provide a list of simple looking identities that are still in need of combinatorial proof.


Review: Crystal Bases Of Q-Deformed Kac Modules Over The Quantum Superalgebras Uq(Gl(Mln)), Gizem Karaali Aug 2014

Review: Crystal Bases Of Q-Deformed Kac Modules Over The Quantum Superalgebras Uq(Gl(Mln)), Gizem Karaali

Pomona Faculty Publications and Research

No abstract provided.


Op-Ed: Solve This Math Problem: The Gender Gap, Francis Su Aug 2014

Op-Ed: Solve This Math Problem: The Gender Gap, Francis Su

All HMC Faculty Publications and Research

Women may not face such blatant impediments to doing math and science today. But Mirzakhani's achievement aside, we are still a long way from adequately recognizing the outstanding work of women.


Math Talk: Preparing Your Conference Presentation, Gizem Karaali Aug 2014

Math Talk: Preparing Your Conference Presentation, Gizem Karaali

Pomona Faculty Publications and Research

If you are a typical reader of this blog, then you recently wrapped up your finals week and then dutifully made a summer plan. And then came the summer. Your plan may have involved working on a manuscript, preparing for a qualifying exam or a new course coming up in the fall, drafting a grant proposal, learning a new language (human or machine), eating kale in four different forms, and perhaps some fun times under the sun. Some, like me, also made plans to travel to conferences and give talks. Gearing up to get ready for my first conference of …


Exponential Decay Of Reconstruction Error From Binary Measurements Of Sparse Signals, Richard Baraniuk, Simon Foucart, Deanna Needell, Yaniv Plan, Mary Wootters Aug 2014

Exponential Decay Of Reconstruction Error From Binary Measurements Of Sparse Signals, Richard Baraniuk, Simon Foucart, Deanna Needell, Yaniv Plan, Mary Wootters

CMC Faculty Publications and Research

Binary measurements arise naturally in a variety of statistical and engineering applications. They may be inherent to the problem—e.g., in determining the relationship between genetics and the presence or absence of a disease—or they may be a result of extreme quantization. A recent influx of literature has suggested that using prior signal information can greatly improve the ability to reconstruct a signal from binary measurements. This is exemplified by onebit compressed sensing, which takes the compressed sensing model but assumes that only the sign of each measurement is retained. It has recently been shown that the number of one-bit measurements …


Four Quotient Set Gems, Stephan Ramon Garcia, Michael Someck '14, Bob Lutz '13, Bryan Brown '15, Michael Dairyko '13 Aug 2014

Four Quotient Set Gems, Stephan Ramon Garcia, Michael Someck '14, Bob Lutz '13, Bryan Brown '15, Michael Dairyko '13

Pomona Faculty Publications and Research

Our aim in this note is to present four remarkable facts about quotient sets. These observations seem to have been overlooked by the MONTHLY, despite its intense coverage of quotient sets over the years.


Near Oracle Performance And Block Analysis Of Signal Space Greedy Methods, Raja Giryes, Deanna Needell Jul 2014

Near Oracle Performance And Block Analysis Of Signal Space Greedy Methods, Raja Giryes, Deanna Needell

CMC Faculty Publications and Research

Compressive sampling (CoSa) is a new methodology which demonstrates that sparse signals can be recovered from a small number of linear measurements. Greedy algorithms like CoSaMP have been designed for this recovery, and variants of these methods have been adapted to the case where sparsity is with respect to some arbitrary dictionary rather than an orthonormal basis. In this work we present an analysis of the so-called Signal Space CoSaMP method when the measurements are corrupted with mean-zero white Gaussian noise. We establish near-oracle performance for recovery of signals sparse in some arbitrary dictionary. In addition, we analyze the block …


The Physicist's Basement, Nora Culik Jul 2014

The Physicist's Basement, Nora Culik

Journal of Humanistic Mathematics

No abstract provided.


The Discipline Of History And The “Modern Consensus In The Historiography Of Mathematics”, Michael N. Fried Jul 2014

The Discipline Of History And The “Modern Consensus In The Historiography Of Mathematics”, Michael N. Fried

Journal of Humanistic Mathematics

Teachers and students of mathematics often view history of mathematics as just mathematics as they know it, but in another form. This view is based on a misunderstanding of the nature of history of mathematics and the kind of knowledge it attempts to acquire. Unfortunately, it can also lead to a deep sense of disappointment with the history of mathematics itself, and, ultimately, a misunderstanding of the historical nature of mathematics. This kind of misunderstanding and the disappointment following from it--both raised to the level of resentment--run through the paper "A Critique of the Modern Consensus in the Historiography of …


A Critique Of The Modern Consensus In The Historiography Of Mathematics, Viktor Blåsjö Jul 2014

A Critique Of The Modern Consensus In The Historiography Of Mathematics, Viktor Blåsjö

Journal of Humanistic Mathematics

The history of mathematics is nowadays practiced primarily by professional historians rather than mathematicians, as was the norm a few decades ago. There is a strong consensus among these historians that the old-fashioned style of history is “obsolete,” and that “the gains in historical understanding are incomparably greater” in the more “historically sensitive” works of today. I maintain that this self-congratulatory attitude is ill-founded, and that the alleged superiority of modern historiographical standards ultimately rests on a dubious redefinition of the purpose of history rather than intrinsic merit.


How Do I Love Thee? Let Me Count The Ways For Syllabic Variation In Certain Poetic Forms, Mike Pinter Jul 2014

How Do I Love Thee? Let Me Count The Ways For Syllabic Variation In Certain Poetic Forms, Mike Pinter

Journal of Humanistic Mathematics

The Dekaaz poetic form, similar to haiku with its constrained syllable counts per line, invites a connection between poetry and mathematics. Determining the number of possible Dekaaz variations leads to some interesting counting observations. We discuss two different ways to count the number of possible Dekaaz variations, one using a binary framework and the other approaching the count as an occupancy problem. The counting methods described are generalized to also count variations of other poetic forms with syllable counts specified, including haiku. We include Dekaaz examples and suggest a method that can be used to randomly generate a Dekaaz variation.


Fields In Math And Farming, Susan D'Agostino Jul 2014

Fields In Math And Farming, Susan D'Agostino

Journal of Humanistic Mathematics

A young woman’s search for a a contemplative, insightful experience leads her from farming to mathematics.


Being Reasonable: Using Brainteasers To Develop Reasoning Ability In Humanistic Mathematics Courses, Gary Stogsdill Jul 2014

Being Reasonable: Using Brainteasers To Develop Reasoning Ability In Humanistic Mathematics Courses, Gary Stogsdill

Journal of Humanistic Mathematics

Developing reasoning ability is often cited as one of the principal justifications of a mathematics requirement for liberal arts undergraduates. Humanistic math courses have become recognized as a paradigm for liberal arts mathematics, but such courses may not provide the opportunity to develop reasoning ability. The author describes his procedure for using brainteasers to promote reasoning in a humanistic math course for liberal arts undergraduates.


Joining ``The Mathematician's Delirium To The Poet's Logic'': Mathematical Literature And Literary Mathematics, Rita Capezzi, Christine Kinsey Jul 2014

Joining ``The Mathematician's Delirium To The Poet's Logic'': Mathematical Literature And Literary Mathematics, Rita Capezzi, Christine Kinsey

Journal of Humanistic Mathematics

This paper describes our team-taught interdisciplinary mathematics and literature course, Mathematical Literature and Literary Mathematics, which invites students to consider Raymond Queneau's challenge: "Why shouldn't one demand a certain effort on the reader's part? Everything is always explained to him. He must eventually tire of being treated with such contempt.'' We study works by Berge, Borges, Calvino, Perec, Queneau, Robbe-Grillet and Stoppard, among others. From a literary critical perspective, the course highlights the play of language rather than the primacy of meaning. We choose texts where mathematical concepts are subjects or structuring elements of the literature, and ideally both. …


Some Effects Of The Human Genome Project On The Erdős Collaboration Graph, Chris Fields Jul 2014

Some Effects Of The Human Genome Project On The Erdős Collaboration Graph, Chris Fields

Journal of Humanistic Mathematics

The Human Genome Project introduced large-scale collaborations involving dozens to hundreds of scientists into biology. It also created a pressing need to solve discrete mathematics problems involving tens of thousands of elements. In this paper, we use minimal path lengths in the Erdős Collaboration Graph between prominent individual researchers as a measure of the distance between disciplines, and we show that the Human Genome Project brought laboratory biology as a whole closer to mathematics. We also define a novel graph reduction method and a metric that emphasizes the robustness of collaborative connections between researchers; these can facilitate the analysis of …


Linear Convergence Of Stochastic Iterative Greedy Algorithms With Sparse Constraints, Nam Nguyen, Deanna Needell, Tina Woolf Jul 2014

Linear Convergence Of Stochastic Iterative Greedy Algorithms With Sparse Constraints, Nam Nguyen, Deanna Needell, Tina Woolf

CMC Faculty Publications and Research

Motivated by recent work on stochastic gradient descent methods, we develop two stochastic variants of greedy algorithms for possibly non-convex optimization problems with sparsity constraints. We prove linear convergence in expectation to the solution within a specified tolerance. This generalized framework applies to problems such as sparse signal recovery in compressed sensing, low-rank matrix recovery, and co-variance matrix estimation, giving methods with provable convergence guarantees that often outperform their deterministic counterparts. We also analyze the settings where gradients and projections can only be computed approximately, and prove the methods are robust to these approximations. We include many numerical experiments which …


Lattices From Elliptic Curves Over Finite Fields, Lenny Fukshansky, Hiren Maharaj Jul 2014

Lattices From Elliptic Curves Over Finite Fields, Lenny Fukshansky, Hiren Maharaj

CMC Faculty Publications and Research

In their well known book Tsfasman and Vladut introduced a construction of a family of function field lattices from algebraic curves over finite fields, which have asymptotically good packing density in high dimensions. In this paper we study geometric properties of lattices from this construction applied to elliptic curves. In particular, we determine the generating sets, conditions for well-roundedness and a formula for the number of minimal vectors. We also prove a bound on the covering radii of these lattices, which improves on the standard inequalities.


Block Kaczmarz Method With Inequalities, Jonathan Briskman, Deanna Needell Jun 2014

Block Kaczmarz Method With Inequalities, Jonathan Briskman, Deanna Needell

CMC Faculty Publications and Research

The randomized Kaczmarz method is an iterative algorithm that solves overdetermined systems of linear equations. Recently, the method was extended to systems of equalities and inequalities by Leventhal and Lewis. Even more recently, Needell and Tropp provided an analysis of a block version of the method for systems of linear equations. This paper considers the use of a block type method for systems of mixed equalities and inequalities, bridging these two bodies of work. We show that utilizing a matrix paving over the equalities of the system can lead to significantly improved convergence, and prove a linear convergence rate as …


Energy Driven Pattern Formation In Planar Dipole-Dipole Systems In The Presence Of Weak Noise, Jaron P. Kent-Dobias '14, Andrew Bernoff Jun 2014

Energy Driven Pattern Formation In Planar Dipole-Dipole Systems In The Presence Of Weak Noise, Jaron P. Kent-Dobias '14, Andrew Bernoff

All HMC Faculty Publications and Research

We study pattern formation in planar fluid systems driven by intermolecular cohesion (which manifests as a line tension) and dipole-dipole repulsion which are observed in physical systems including ferrofluids in Hele-Shaw cells and Langmuir layers. When the dipolar repulsion is sufficiently strong, domains undergo forked branching reminiscent of viscous fingering. A known difficulty with these models is that the energy associated with dipole-dipole interactions is singular at small distances. Following previous work, we demonstrate how to ameliorate this singularity and show that in the macroscopic limit, only the relative scale of the microscopic details of a system are relevant, and …


Two-Part Reconstruction With Noisy-Sudocodes, Yanting Ma, Dror Baron, Deanna Needell Jun 2014

Two-Part Reconstruction With Noisy-Sudocodes, Yanting Ma, Dror Baron, Deanna Needell

CMC Faculty Publications and Research

We develop a two-part reconstruction framework for signal recovery in compressed sensing (CS), where a fast algorithm is applied to provide partial recovery in Part 1, and a CS algorithm is applied to complete the residual problem in Part 2. Partitioning the reconstruction process into two complementary parts provides a natural trade-off between runtime and reconstruction quality. To exploit the advantages of the two-part framework, we propose a Noisy-Sudocodes algorithm that performs two-part reconstruction of sparse signals in the presence of measurement noise. Specifically, we design a fast algorithm for Part 1 of Noisy-Sudocodes that identifies the zero coefficients of …


Why You Need A Summer Plan, Gizem Karaali May 2014

Why You Need A Summer Plan, Gizem Karaali

Pomona Faculty Publications and Research

In the last decade, for many times, I have tasted first-hand the end-of-summer blues I described above. I have spent many early spring months dreaming of all that I would be doing when the summer arrives, only to realize that it was already September and I had not much to show for for the months in between. I have also observed many of my peers going through similar things, and I just assumed for years that this was how it had to be. But then some time in the middle of the tenure track, I decided to try approaching my …


Improving Image Clustering Using Sparse Text And The Wisdom Of The Crowds, Anna Ma, Arjuna Flenner, Deanna Needell, Allon G. Percus May 2014

Improving Image Clustering Using Sparse Text And The Wisdom Of The Crowds, Anna Ma, Arjuna Flenner, Deanna Needell, Allon G. Percus

CMC Faculty Publications and Research

We propose a method to improve image clustering using sparse text and the wisdom of the crowds. In particular, we present a method to fuse two different kinds of document features, image and text features, and use a common dictionary or “wisdom of the crowds” as the connection between the two different kinds of documents. With the proposed fusion matrix, we use topic modeling via non-negative matrix factorization to cluster documents.


Review: Truncated Toeplitz Operators Of Finite Rank, Stephan Ramon Garcia May 2014

Review: Truncated Toeplitz Operators Of Finite Rank, Stephan Ramon Garcia

Pomona Faculty Publications and Research

No abstract provided.


The Fundamental Principle Of Productivity: What They Don't Teach You In Graduate School, Gizem Karaali Apr 2014

The Fundamental Principle Of Productivity: What They Don't Teach You In Graduate School, Gizem Karaali

Pomona Faculty Publications and Research

But through the years, I have read many books, ranging from self-help guides to creative writing manuals, attended workshops, frequented relevant websites, and reflected upon my own personal experiences. As a result, I have collected together a few ideas and tools on productivity and time management that have been working well for me. In this post I want to share with you the most basic of these principles, with the hope that it may assist you in your life, at whatever stage you are. Whether you are a graduate student, a postdoctoral researcher, a junior mathematician on the tenure track, …


The Scientist–Reporter Collaboration: A Guide To Working With The Press, Rachel Levy, Flora Lichtman, David L. Hu Apr 2014

The Scientist–Reporter Collaboration: A Guide To Working With The Press, Rachel Levy, Flora Lichtman, David L. Hu

All HMC Faculty Publications and Research

Science, technology, engineering, and mathematics (STEM) to the public can be challenging. Often, the language that researchers use among themselves is technical and difficult for non-experts to decipher. But as you probably know, communicating your research to non-experts is becoming mandatory. In a direct sense, funding agencies often require outreach for grant fulfillment. There are indirect benefits as well: Conveying the joy of discovery and the relevance of scientific results builds scientific literacy among the public---which of course includes both students who will eventually do research of their own and people who elect the policy makers who allocate funding. How …


Aftermath: Every Math Major Should Take A Public-Speaking Course, Rachel Levy Apr 2014

Aftermath: Every Math Major Should Take A Public-Speaking Course, Rachel Levy

All HMC Faculty Publications and Research

Rachel Levy argues that all mathematics majors should learn the art of public speaking.


Guaranteed Sparse Signal Recovery With Highly Coherent Sensing Matrices, Guangliang Chen, Atul Divekar, Deanna Needell Apr 2014

Guaranteed Sparse Signal Recovery With Highly Coherent Sensing Matrices, Guangliang Chen, Atul Divekar, Deanna Needell

CMC Faculty Publications and Research

Compressive sensing is a methodology for the reconstruction of sparse or compressible signals using far fewer samples than required by the Nyquist criterion. However, many of the results in compressive sensing concern random sampling matrices such as Gaussian and Bernoulli matrices. In common physically feasible signal acquisition and reconstruction scenarios such as super-resolution of images, the sensing matrix has a non-random structure with highly correlated columns. Here we present a compressive sensing type recovery algorithm, called Partial Inversion (PartInv), that overcomes the correlations among the columns. We provide theoretical justification as well as empirical comparisons.


Greedy Signal Space Methods For Incoherence And Beyond, Raja Giryes, Deanna Needell Mar 2014

Greedy Signal Space Methods For Incoherence And Beyond, Raja Giryes, Deanna Needell

CMC Faculty Publications and Research

Compressive sampling (CoSa) has provided many methods for signal recovery of signals compressible with respect to an orthonormal basis. However, modern applications have sparked the emergence of approaches for signals not sparse in an orthonormal basis but in some arbitrary, perhaps highly overcomplete, dictionary. Recently, several "signal-space" greedy methods have been proposed to address signal recovery in this setting. However, such methods inherently rely on the existence of fast and accurate projections which allow one to identify the most relevant atoms in a dictionary for any given signal, up to a very strict accuracy. When the dictionary is highly overcomplete, …


Review: The Relationships Among Multiplicities Of A J-Self-Adjoint Differential Operator's Eigenvalue, Stephan Ramon Garcia Mar 2014

Review: The Relationships Among Multiplicities Of A J-Self-Adjoint Differential Operator's Eigenvalue, Stephan Ramon Garcia

Pomona Faculty Publications and Research

No abstract provided.


Stochastic Gradient Descent, Weighted Sampling, And The Randomized Kaczmarz Algorithm, Deanna Needell, Nathan Srebro, Rachel Ward Mar 2014

Stochastic Gradient Descent, Weighted Sampling, And The Randomized Kaczmarz Algorithm, Deanna Needell, Nathan Srebro, Rachel Ward

CMC Faculty Publications and Research

We obtain an improved finite-sample guarantee on the linear convergence of stochastic gradient descent for smooth and strongly convex objectives, improving from a quadratic dependence on the conditioning (L/µ) 2 (where L is a bound on the smoothness and µ on the strong convexity) to a linear dependence on L/µ. Furthermore, we show how reweighting the sampling distribution (i.e. importance sampling) is necessary in order to further improve convergence, and obtain a linear dependence in the average smoothness, dominating previous results. We also discuss importance sampling for SGD more broadly and show how it can improve convergence also in other …