# Home Colloquium

**First and third Tuesdays of each month at noon in Goodrich 104.**

*"A light pizza lunch will be served."*

The Mathematics & Computer Science Colloquium is a series of talks during the school year meant to enrich the mathematical knowledge of the community, independent of any courses attenders may be taking. Although many talks are on upper-level mathematical topics, the main ideas should be intelligible to students who have had calculus. In addition to talks by members of the mathematics department, students give some of the talks, and we have several outside speakers each year. Upcoming colloquia and a list of the colloquium talks for the last several years follow.

**Mathematics and Computer Science Colloquia 2001-2002**

**Upcoming Colloquia**

Apr. 9 - Prof. Marcela Perlwitz (Education) & Prof. Michael Axtell (Math & CS), "Linguistic Activity & Cognitive Development of Mathematical Concepts."

Abstract: Consideration of linguistic activity, cognitive development, and mathematics as psychological and social activities help us explain the nature of students' understanding of mathematics in relation to classroom discursive practices.Jan. 22 - Prof. William Turner, "Black Box Linear Algebra." Prof. Turner is from North Carolina State University and is a candidate for a computational science position in the department.

Jan 15 - Prof. Dennis Krause, Wabash Physics Department. "Quantum Game Theory: How to Win Big with Quantum Mechanics."

Nov 6 - Prof. David Maharry, Wabash Math & CS Department. "If You Think You Have Big Problems, Try a Parallel Computer."

Oct 16 - Prof. John George, Wabash Math & CS Department. "The Catalan Numbers"

Abstract:Given a polygon of n+2 sides, in how many ways can we dissect it into triangles by drawing non-intersecting diagonals? Given a product of n+1 letters, in how many ways can we parenthesize the product so that there are two factors inside each pair of parentheses? Given an election with two candidates A and B, where each candidate receives n votes, how many ways can the votes come in so that candidate A is never behind candidate B? It is somewhat surprising that all of these questions have the same answers, and even more surprising that the same answers also apply to many dozens of other problems in pure mathematics and computer science, all apparently different. This lecture is aimed to be comprehensible to those who know little or no mathematics.Oct 2 - Prof. Walter D. Wallis, Southern Illinois University, "Latin Squares for Those That Know No Latin."

Abstract:A Latin square is a square array, each of whose rows and columns is an arrangement of the same set. We shall discuss the existence of these arrays, their origins in puzzles, and their applications in Pure Mathematics and in Experimental Design. Althought the listener will require no further background than knowing the definition of a matrix, we shall be able to describe some current mathematical research problems.Sep 18 - Professor Bert Barreto, Wabash Economics Department, "PROGRESS to Regress via LMS is a Mess?"

Sep 4 - Professor Robert Foote (with Anand Jha, '02), "PoincareDraw II: An Interactive Program for Teaching and Learning Hyperbolic Geometry."

**Mathematics and Computer Science Colloquia 2000-2001**

May 9 - Dr. Farid O. Farid, Pacific Lutheran University, "Topics on the Eigenvalue Problem." Dr. Farid is a candidate for a one year position in Mathematics.

Apr 17 - Dr. J.D. Phillips, St. Mary's College-California, will give a presentation titled, "Loops and Groups, the Latest Scoop." Dr. Phillips is a tenure track candidate for Chair of the Math & CS Department.

Apr 12 - Dr. Dan Coroian, Indiana-Purdue University -Ft.Wayne, "Click This! - A Survey of Mathematical Software". Prof. Coroian is a candidate for a tenure track position in Computer Science.

Apr 10 - CANCELLED! John Marden, Professor of Statistics, University of Illinois, Spatial RanksPositioning Multivariate Data.

Mar 13 - Nathan Risk, Wabash Class of '92, An Introduction to Neural Networks.Feb 20 - Professor Humberto Barreto, Wabash College, Is A-Rod Worth a Quarter Billion, or, a Random Number Generator, Visual Basic, and Monte Carlo Simulation Meet Baseball. Download the Excel/Visual Basic program he used in his talk!Feb 1 - Professor George Exner, Bucknell University, "How Many Ways Are There to be Deranged? or The Bernoulli Letter Problem" Jan 24 - Professor Peter Hamburger, Indiana-Purcue University - Fort Wayne, and a candidate for a position in Math & CS "Coded Secrets Behind Doodles & Doilies."Abstract:If you are a compulsive doodler, or if you crochet doilies, then you will enjoy this presentation; if not, you can still appreciate it. In this talk, we will learn how to create pretty symmetrical drawings from doodles. In this journey, there will be some geometry, number theory, group theory, and some graph theory and combinatorics topics such as codes, dual graphs, symmetrical and maximal chains, and others. This also will answer a conjecture of B. Grunnbaum, which goes back to D.W. Henderson, and even further back to Euler and Venn.

Jan 23 - Professor Maynard Thompson, Indiana University, Why is it Difficult for a Group to Make a Decision?

Nov 14 - Professor Scott Feller, Wabash College, Building a Supercomputer for Computational Chemistry.

Oct 31 - Professor Kerry Smith, Franklin College. The Mathematics of Huffman Codes.

Oct 17 - Professor Damon Scott, Wabash College, Transformations of Sonorities: What Happens Between the Chords.

Oct 3 - Professor Michael Axtell, Wabash College, Teaching Calculus With Projects.

Sept 19 - Professor Charles S. Holmes, Miami University, Rubiks Cube: An Invertible Function Factory

Sept 5 - Professor Robert L. Foote, Wabash College, "Circumferences of Convex Regions: *C = *2p*r *Isn't Just for Circles Anymore!"

**Mathematics and Computer Science Colloquia 1999-2000**

April 18 - Gary J. Sherman, Rose-Hulman Institute of Technology, "What's a 'Closed with a Twist' Set (cwatset)?"

ABSTRACT: A cwatset is a subset of binary n-space that is 'nearly' a subgroup. The development---indeed the undergraduate driven development--- of cwatsets from their roots in statistics through their combinatorial and group-theoretic properties will be traced to open questions suitable for undergraduate research.

Apr 11 - Robert Dirks, Wabash '00, "The Probabilistic Method: A Useful Tool for Proofs of Existence."

Mar 21 - Peter Thompson, Mathematics & Computer Science Department, Wabash College, "How Many 1's Should You Get in 2 and 1/2 Rolls of a Die? Binomial's with Non-Integer-n's and Their Applications."

Feb 24 - David Weinreich, The University of Memphis, "The Speed & Structure of Hereditary Graph Properties"

ABSTRACT: A hereditary graph property is a set of labeled graphs with certain closure conditions. The speed of a property P is |P^n|, the number of graphs in the property on n labeled vertices. Surprisingly, speeds of hereditary properties fall into a hierarchy of functional ranges, in many cases asymptotically following a "nice" function. Furthermore, the structure of graphs in the property is described by the property's speed, and vice-versa. In this talk we give an overview of what is known about hereditary graph properties and suggest directions for future research. No background in graph theory is required for this talk.

Feb 15 - Michael Axtell, The University of Iowa, "Secret Life Behind Bars."

Feb 1 - Dan Singer, Mathematics & Computer Science Department, Wabash College, "On Catalan Trees and Formal Power Series Inversion"

Jan 18 - Thomas Sellke, '76, Statistics Department, Purdue University, "P-Values Don't Mean What You Think They Do"

Dec 8 - Dennis Krause, Physics Department Wabash College, "Looking Beyond 3-D: How to Understand and Search for New Compact Dimensions"

Nov 16 - Jeffrey Z. Anderson, '92, Industrial Engineer for the Commonwealth Aluminum Corporation in Lewisport, KY, "Applying Operations Research in the Aluminum Industry."

Nov 2 - Gregory Galperin, Eastern Illinois University, "Billiards Compute all Decimal Digits of p!"

ABSTRACT: A very simple dynamical system will be considered at the talk: two elastically colliding balls and one reflecting wall. It turns out that this system "counts" p with any accuracy you wish!

To explain this amazing phenomenon, one needs to look at the given dynamical system from the purely geometric point of view. The geometry originates from the concept of the configuration and the phase space of a system and allows one to investigate a related billiard system. These spaces help to investigate various difficult problems in the theory of billiards, in particular, a problem on periodic billiard trajectories in a polygon.

Professor Galperin will speak again in the geometry class (Math 21) on Wednesday, Nov 3, at 11:20 in D 220

on "A Tale of Three Circles."

ABSTRACT: Three circles in the plane form a curvilinear triangle. What is the sum of its interior angles? The answer to the question depends on the circles' positions in the plane and is connected with the three famous geometries: Euclidean, spherical, and hyperbolic. The speaker will demonstrate different models of the three geometries based on the three circles problem.

**Mathematics and Computer Science Colloquia 1999-2000**

- Oct 19 - Peter Saveliev, Wabash College, "A Problem of Two Gamblers and An Introduction to Topology."
- Oct 5 - Humberto Barreto, Chair Wabash Department of Economics, "The Comparative Statics Wizard has no Clothes: An Introduction to Visual Basic."
- Sep 21 - William Swift, Wabash College Emeritus, "A Plane Filling Curve"
- Sep 7 - Robert Foote, Wabash College, "Geometry of the Prytz Planimeter"

**Mathematics and Computer Science Colloquia 1998-99**

- Apr 22 - Mr. Daniel Singer, University of California, San Diego, "Partition Identities and the Involution Principle"
- Apr 20 - Mr. Daniel Smith, Univ. of Illinois, Urbana-Champaign, "The Ubiquity of p"
- Apr 6 - Dr. John Maharry, Franklin College, "Good Will Hunting and Random Walks"
- Mar 16 - Robert, Wabash '00, "Hyperbolic Tilings and Abstract Algebra"
- March 2 - David Whitaker, Wabash '99, "The History and Development of Cryptography"
- Feb 9 - Dr. Warren Koepp, Texas A&M University at Commerce, "Chinese Astrology, Clock Arithmetic, and Compatibility Partitions of Commutative Groups"
- Feb 4 - Dr. Robert Leese, St. Catherine's College, Oxford University - "Lattice Labelings, Traveling Salesmen, and the Radio Spectrum"
- Feb 2 - Ms. Wendy Weber, University of Kentucky - "Finding Lost Triangles: Recovering Triangulations of Polyhedra"
- Jan. 19 - Thomas Tegtmeyer, Wabash College - "Life in a Multiply Connected Domain"
- Dec. 1 - Prof. William Swift, Emeritus, Wabash College - "Nim and Games Akin:
- Nov. 17 - Dr. Xiangfei Zeng, Allstate Insurance Company - "Hurrican Modeling & Insurance Pricing"
- Nov. 5 - Dr. M. Patrick Goda, '93 - "Commodity Parallel Processing and Rationale"
- Nov. 3 - Michael Orrison, '95, Darmouth College - "Young Tableaux"
- Nov. 5 - Dr. M. Patrick Goda, '93 - "Commodity Parallel Processing and Rationale"
- Oct. 6 - Dr. Allison Wolf, Wabash College - "Variations on Hamilton's Game"
- Sep. 15 - Dr. Robert Foote, Wabash College - "The Inverted Pendulum: Which Way Will It Fall?"

**Mathematics and Computer Science Colloquia 1997-98**

- Apr 14 - Prof. Rebecca Doerges - Statistics Dept., Purdue - "Mapping Genes in Experimental Organisms"
- Apr 9 - Ms. Allison Wolf - Dept. of Math, Emory University - "On Coloring Graphs"
- Apr 7 - Ms. Michelle Lemasurier - Dept. of Math, Univ. of Georgia

"A Relationship between the shape of a surface and the vector fields that can be defined on it:

The Poincare-Hopf Theorem"

- Apr 2 - Prof. Craig Roberts, Dept. of Math, U. of Arkansas, Monticello

"Tessellations - The Reason Bob Vila Should have been a Mathematician!"

- Mar 24 - Dollena Hawkins, Dept. of Math, University of Kentucky - "What's Normal?"
- Mar 19 - Peter Thompson, Wabash College - "Binomials, Betas, Beta-Binomials, and Babies"
- Mar 17 - Paul Loomis '92, Purdue - "A Homegrown Sequence and a Famous Problem"
- Mar 3 - Paul Roback, Dept. of Statistics, Colorado State Univ - "Counting Whales"
- Feb 23 - Ruth Pfeiffer, Dept of Math Statistics, University of Maryland

"Two Statistical Problems for Stochastic Processes with Hysteresis"

- Feb 17 - Yung-Pin Chen, Department of Mathematics, Smith College - "How many balls are in the urn?"
- Feb 3 - Prof. Bonnie Gold, Math Dept., Wabash College

"Automatic Differentiation: Computing Derivative Values without Derivative Formulas"

- Jan 20 - Prof. William Swift - Wabash College - "Convolution: Gateway to Mathematics"
- Dec 2 - Rodney Lynch, Wabash College '89 - "Another Look at the Division Algorithm"
- Nov 18 - Peter Thompson, Mathematics Department, Wabash College

"Reducing the Effect of the Initial Matchups in Double Elimination Tournaments"

- Nov 4 - Mary Ellen Bock, Department of Statistics, Purdue University - "Using Wavelets in Statistics"
- Oct 7 - Jon Sorenson, Computer Science Department, Butler Univeristy

"Genetic algorithms and the Extended GCD problem"

- Sep 16 - Robert Foote, Mathematics Department, Wabash College - "Planimeters and the Isoperimetric Inequality"

**Mathematics and Computer Science Colloquia 1996-97**

- April 22 David Maharry, Computer Science, Wabash College: "Dynamic Programming: Connecting DNA Sequences and Matrix Multiplication"
- April 8 Liang Huang, Mathematics Department, Rockford College: "Continuation Method and Eigenvalue Problems."
- Mar 18 Charles Jones, Mathematics Department, Grinnell College: "Costas Arrays, a.k.a. Arranging a Radar Array"
- Mar 4 Stefan Treatman, Mathematics Department, Wabash College: "Continued Fractions: They keep going and going"
- Feb 18 Greg Buzzard, Mathematics Department, Indiana University "How many times am I supposed to do this? An introduction to iteration."
- Feb 4 Bert Barreto, Economics Department, Wabash College: "Quantitative Potpourri: Excel, Pedagogy, Regression, and Visual Basic"
- Jan 21 Sesha Dassanayake, Senior Mathematics major, Wabash College: "Infinite Descent: A Method to solve a wide variety of problems"
- Dec 3 John Sullivan, University of Illinois
- Nov 19 Fabio Milner, Mathematics Department, Purdue University: "Mathematical Models of Demographics and Epidemics"
- Nov 5 Esteban Poffald, Mathematics Department, Wabash College: "Fractals and Transformations"
- Oct 15 Sanjiva Weerawarana, Computer Science, Purdue University: "Net-centric Computing on the World Wide Web: The Net //ELLPACK Approach"
- Oct 1 Joe West, Physics Department, Wabash College: "Physicists: Machiavellian Mathematicians or Approximating Anarchists"
- Sep 17 Paul Mielke, Professor Emeritus of Mathematics, Wabash College: "Combinations of Primes"

**Mathematics and Computer Science Colloquia 1995-96**

- Sep 5 Bill Swift, "Counting Beyond Infinity II"
- Sep 19 Robert Foote and Nathan Fouts, '97, "Cruising in Hyperbolic Space: Interactive Non-Euclidean Geometry"
- Oct 3 Carl Cowen, Purdue, "Using BIG Numbers to keep BIG secrets"
- Nov 7 Dan Maki, Indiana University, "The Mathematics of Speech Recognition using Computers"
- Nov 21 John Maharry, Ohio State Univ., "Graph Connectivity: You can't get there from here!"
- Dec 5 Bonnie Gold, "The Gnome inside your calculator: Just how does that little guy find the sin(2)?"
- Jan 1 Kyle Falconbury, '96, "Morley's Theorem"
- Feb 6 David Moore, Purdue Univ., "Statistical Thinking: How to tell the Facts from the Artifacts"
- Feb 20 John Skillings, U. of Miami (OH), "Modeling Policy Sales for an Insurance Company"
- Mar 19 Tom Sellke, Statistics Department, Purdue University: "How far is WAY out?: Chebshev Inequalities for Unimodal Probability Distributions"
- Mar 28 Kenneth Ross, U. of Oregon, "The Mathematics of Card Shuffling"

**Mathematics and Computer Science Colloquia 1994-95**

- Sep 6 Bill Swift: "The Two Box Paradox"
- Set 20 Fei Zeng: "The Gambler's Ruin"
- Oct 4 Bob Cooley: "ab <> ba"
- Nov 1 Jay Wood, Purdue Univ - Calumet, "Codes and the Fourier Transform"
- Nov 11 Jamshid Nazari, Purdue, "Development of Algorithms for Generalization, Convergence, and Parallelization in Neural Networks"
- Nov 15 Glen Helman, "Proofs and Functions"
- Dec 9 Roger Lautzenheiser, RHIT, "What Does It All MEAN?"
- Jan 24 David Wilson, "Where's X?"
- Feb 7 Brian Poole, '88, and Tim Schutz, '93, American States Insurance, "Actuarial Science: A Career Perspective"
- Feb 21 Michael Orrison, '95, "The Hausdorff Paradox, or, 1/2 + 1/3 + 1/3 = 1"
- Mar 21 Robert Foote, "What is an Integral?"
- Apr 4 John Van Drie, '74, Upjohn Co, "Reflections, Handedness, and Spinors"
- Apr 18 John Bailer, Miami University of Ohio, "Uncertainty in the Assessment of Hazards to Human Health."

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