Mathematical People: Profiles and Interviews
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Uniform Polychora
BRIDGES Mathematical Connections in Art, Music, and Science Uniform Polychora Jonathan Bowers 11448 Lori Ln Tyler, TX 75709 E-mail: [email protected] Abstract Like polyhedra, polychora are beautiful aesthetic structures - with one difference - polychora are four dimensional. Although they are beyond human comprehension to visualize, one can look at various projections or cross sections which are three dimensional and usually very intricate, these make outstanding pieces of art both in model form or in computer graphics. Polygons and polyhedra have been known since ancient times, but little study has gone into the next dimension - until recently. Definitions A polychoron is basically a four dimensional "polyhedron" in the same since that a polyhedron is a three dimensional "polygon". To be more precise - a polychoron is a 4-dimensional "solid" bounded by cells with the following criteria: 1) each cell is adjacent to only one other cell for each face, 2) no subset of cells fits criteria 1, 3) no two adjacent cells are corealmic. If criteria 1 fails, then the figure is degenerate. The word "polychoron" was invented by George Olshevsky with the following construction: poly = many and choron = rooms or cells. A polytope (polyhedron, polychoron, etc.) is uniform if it is vertex transitive and it's facets are uniform (a uniform polygon is a regular polygon). Degenerate figures can also be uniform under the same conditions. A vertex figure is the figure representing the shape and "solid" angle of the vertices, ex: the vertex figure of a cube is a triangle with edge length of the square root of 2. -
Platonic Solids Generate Their Four-Dimensional Analogues
1 Platonic solids generate their four-dimensional analogues PIERRE-PHILIPPE DECHANT a;b;c* aInstitute for Particle Physics Phenomenology, Ogden Centre for Fundamental Physics, Department of Physics, University of Durham, South Road, Durham, DH1 3LE, United Kingdom, bPhysics Department, Arizona State University, Tempe, AZ 85287-1604, United States, and cMathematics Department, University of York, Heslington, York, YO10 5GG, United Kingdom. E-mail: [email protected] Polytopes; Platonic Solids; 4-dimensional geometry; Clifford algebras; Spinors; Coxeter groups; Root systems; Quaternions; Representations; Symmetries; Trinities; McKay correspondence Abstract In this paper, we show how regular convex 4-polytopes – the analogues of the Platonic solids in four dimensions – can be constructed from three-dimensional considerations concerning the Platonic solids alone. Via the Cartan-Dieudonne´ theorem, the reflective symmetries of the arXiv:1307.6768v1 [math-ph] 25 Jul 2013 Platonic solids generate rotations. In a Clifford algebra framework, the space of spinors gen- erating such three-dimensional rotations has a natural four-dimensional Euclidean structure. The spinors arising from the Platonic Solids can thus in turn be interpreted as vertices in four- dimensional space, giving a simple construction of the 4D polytopes 16-cell, 24-cell, the F4 root system and the 600-cell. In particular, these polytopes have ‘mysterious’ symmetries, that are almost trivial when seen from the three-dimensional spinorial point of view. In fact, all these induced polytopes are also known to be root systems and thus generate rank-4 Coxeter PREPRINT: Acta Crystallographica Section A A Journal of the International Union of Crystallography 2 groups, which can be shown to be a general property of the spinor construction. -
Herman Heine Goldstine
Herman Heine Goldstine Born September 13, 1913, Chicago, Ill.; Army representative to the ENIAC Project, who later worked with John von Neumann on the logical design of the JAS computer which became the prototype for many early computers-ILLIAC, JOHNNIAC, MANIAC author of The Computer from Pascal to von Neumann, one of the earliest textbooks on the history of computing. Education: BS, mathematics, University of Chicago, 1933; MS, mathematics, University of Chicago, 1934; PhD, mathematics, University of Chicago, 1936. Professional Experience: University of Chicago: research assistant, 1936-1937, instructor, 1937-1939; assistant professor, University of Michigan, 1939-1941; US Army, Ballistic Research Laboratory, Aberdeen, Md., 1941-1946; Institute for Advanced Study, Princeton University, 1946-1957; IBM: director, Mathematics Sciences Department, 1958-1965, IBM fellow, 1969. Honors and Awards: IEEE Computer Society Pioneer Award, 1980; National Medal of Science, 1985; member, Information Processing Hall of Fame, Infornart, Dallas, Texas, 1985. Herman H. Goldstine began his scientific career as a mathematician and had a life-long interest in the interaction of mathematical ideas and technology. He received his PhD in mathematics from the University of Chicago in 1936 and was an assistant professor at the University of Michigan when he entered the Army in 1941. After participating in the development of the first electronic computer (ENIAC), he left the Army in 1945, and from 1946 to 1957 he was a member of the Institute for Advanced Study (IAS), where he collaborated with John von Neumann in a series of scientific papers on subjects related to their work on the Institute computer. In 1958 he joined IBM Corporation as a member of the research planning staff. -
Platonic Solids Generate Their Four-Dimensional Analogues
This is a repository copy of Platonic solids generate their four-dimensional analogues. White Rose Research Online URL for this paper: https://eprints.whiterose.ac.uk/85590/ Version: Accepted Version Article: Dechant, Pierre-Philippe orcid.org/0000-0002-4694-4010 (2013) Platonic solids generate their four-dimensional analogues. Acta Crystallographica Section A : Foundations of Crystallography. pp. 592-602. ISSN 1600-5724 https://doi.org/10.1107/S0108767313021442 Reuse Items deposited in White Rose Research Online are protected by copyright, with all rights reserved unless indicated otherwise. They may be downloaded and/or printed for private study, or other acts as permitted by national copyright laws. The publisher or other rights holders may allow further reproduction and re-use of the full text version. This is indicated by the licence information on the White Rose Research Online record for the item. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ 1 Platonic solids generate their four-dimensional analogues PIERRE-PHILIPPE DECHANT a,b,c* aInstitute for Particle Physics Phenomenology, Ogden Centre for Fundamental Physics, Department of Physics, University of Durham, South Road, Durham, DH1 3LE, United Kingdom, bPhysics Department, Arizona State University, Tempe, AZ 85287-1604, United States, and cMathematics Department, University of York, Heslington, York, YO10 5GG, United Kingdom. E-mail: [email protected] Polytopes; Platonic Solids; 4-dimensional geometry; Clifford algebras; Spinors; Coxeter groups; Root systems; Quaternions; Representations; Symmetries; Trinities; McKay correspondence Abstract In this paper, we show how regular convex 4-polytopes – the analogues of the Platonic solids in four dimensions – can be constructed from three-dimensional considerations concerning the Platonic solids alone. -
CMS NOTES De La SMC
CMS NOTES de la SMC Volume 31 No. 1 February / fevrier´ 1999 In this issue / Dans ce numero´ FROM THE it did at Kingston. I want to thank PRESIDENT’S DESK all the organizers of the meeting, no- Editorial ..................... 2 tably the joint Meeting Directors, Tony Geramita and David Wehlau, and the Letter to the Editors .......... 3 Local Arrangements Committee, Leo Jonker and Fady Alajaji, for all their Education Notes ............. 3 work. The session organizers, many from the Kingston mathematical com- Du bureau du president´ ...... 5 munity, displayed great initiative and are the key reason for the success of Awards / Prix ................ 7 the meeting. Let me now turn to a number of Camel Bytes ................. 9 developments within the CMS, all of which were discussed at the December Meetings / Reunions´ Richard Kane Executive and Board meetings. Firstly, CMS Summer 1999 Meeting the Kingston meeting marked the offi- Reunion´ d’et´ e´ 1999 de la SMC 10 (voir la page 5 pour la version cial establishment of one of the most About AARMS ............. 19 franc¸aise) exciting developments within the CMS In this report, I will focus on three in recent years, namely the CMS En- Abstract Form / Formulaire de initiatives which were considered by dowment Grants (EG) Program. The resum´ e´ .................... 20 the CMS Executive and Board at our Board accepted the final report of the Registration form / Formulaire Kingston Winter meeting in Decem- Endowment Fund Task Force, chaired d’inscription ............... 22 ber. But before moving to these items, by Eddy Campbell, with its recommen- I want to warmly congratulate all of dation for the establishment of the EG Call for Nominations / Appel de the organizers of the meeting for their program. -
Platform Systems Vs. Step Processes—The Value of Options and the Power of Modularity by Carliss Y
© Carliss Y. Baldwin Comments welcome. Design Rules, Volume 2: How Technology Shapes Organizations Chapter 13 Platform Systems vs. Step Processes—The Value of Options and the Power of Modularity By Carliss Y. Baldwin Note to Readers: This is a draft of Chapter 13 of Design Rules, Volume 2: How Technology Shapes Organizations. It builds on prior chapters, but I believe it is possible to read this chapter on a stand-alone basis. The chapter may be cited as: Baldwin, C. Y. (2019) “Platform Systems vs. Step Processes—The Value of Options and the Power of Modularity,” HBS Working Paper (January 2019). I would be most grateful for your comments on any aspect of this chapter! Thank you in advance, Carliss. Abstract The purpose of this chapter is to contrast the value structure of platform systems (e.g. a computer) with step processes (e.g. an assembly line). I first review the basic technical architecture of computers and argue that every computer is inherently a platform for performing computations as dictated by their programs. I state and prove five propositions about platform systems, which stand in contrast to the propositions derived for step processes in Chapter 8. The propositions suggest that platform systems and step processes call for different forms of organization. Specifically, step processes reward technical integration, unified governance, risk aversion, and the use of direct authority, while platform systems reward modularity, distributed governance, risk taking, and autonomous decision-making. Despite these differences, treating platform systems and step processes as mutually exclusive architectures sets up a false dichotomy. Creating any good requires carrying out a technical recipe, i.e., performing a series of steps. -
TME Volume 5, Numbers 2 and 3
The Mathematics Enthusiast Volume 5 Number 2 Numbers 2 & 3 Article 27 7-2008 TME Volume 5, Numbers 2 and 3 Follow this and additional works at: https://scholarworks.umt.edu/tme Part of the Mathematics Commons Let us know how access to this document benefits ou.y Recommended Citation (2008) "TME Volume 5, Numbers 2 and 3," The Mathematics Enthusiast: Vol. 5 : No. 2 , Article 27. Available at: https://scholarworks.umt.edu/tme/vol5/iss2/27 This Full Volume is brought to you for free and open access by ScholarWorks at University of Montana. It has been accepted for inclusion in The Mathematics Enthusiast by an authorized editor of ScholarWorks at University of Montana. For more information, please contact [email protected]. The Montana Mathematics Enthusiast ISSN 1551-3440 VOL. 5, NOS.2&3, JULY 2008, pp.167-462 Editor-in-Chief Bharath Sriraman, The University of Montana Associate Editors: Lyn D. English, Queensland University of Technology, Australia Claus Michelsen, University of Southern Denmark, Denmark Brian Greer, Portland State University, USA Luis Moreno-Armella, University of Massachusetts-Dartmouth International Editorial Advisory Board Miriam Amit, Ben-Gurion University of the Negev, Israel. Ziya Argun, Gazi University, Turkey. Ahmet Arikan, Gazi University, Turkey. Astrid Beckmann, University of Education, Schwäbisch Gmünd, Germany. John Berry, University of Plymouth,UK. Morten Blomhøj, Roskilde University, Denmark. Robert Carson, Montana State University- Bozeman, USA. Mohan Chinnappan, University of Wollongong, Australia. Constantinos Christou, University of Cyprus, Cyprus. Bettina Dahl Søndergaard, University of Aarhus, Denmark. Helen Doerr, Syracuse University, USA. Ted Eisenberg, Ben-Gurion University of the Negev, Israel. -
We're All on a Journey
FOR 5O YEARS JEWISH FOUNDATION OF MANITOBA you've made a difference 2014 ANNUAL REPORT We thank you. Your community thanks you. We’re all on a journey. Volunteers at 12/14 Staff at 06/15 Board of Directors Committees of Scholarship Committee Marsha Cowan Alex Serebnitski, Chair Chief Executive Officer We’re all on a journey. Executive the Foundation Danita Aziza Joseph J. Wilder, Q.C., Ian Barnes Audit Committee Richard Boroditsky President Chief Financial Officer Michael Averbach, Chair Ahava Halpern Steven J. Kroft, Celia (Ceci) Gorlick, Q.C. Rishona Hyman Marla Aronovitch Past President Steven Kohn Mirtha Lopez Grants & Distributions Anita Wortzman, Jeff Norton Maylene Ludwig Officer President-Elect reflections on impact Rimma Pilat Aaron Margolis Dr. Eric Winograd, Patti Boorman Danny Stoller Rimma Pilat Secretary-Treasurer Director of Operations Eric Winograd Rocky Pollack Celia (Ceci) Gorlick, Q.C. Lonny Ross Stephanie Casar Sherman Greenberg Endowment Book of Life Jerry Shrom Administrative Assistant Larry Vickar Committee Ruth Carol Feldman, Chair Leandro Zylberman Katarina Kliman Members of the Board Morley Bernstein Special Awards Committee Manager of They say that a journey of 1,000 These three men first gathered in individuals who are on their own Michael Averbach Terri Bernstein Steven Hyman, Chair Donor Relations miles begins with the first step. As the October 1963 to lay the groundwork journeys. To help some organizations Cynthia Hiebert-Simkin Susan Halprin Bonnie Cham Pamela Minuk 50th anniversary year of the Jewish for what was to become the JFM. A and individuals take that all-important David Kroft Peter Leipsic Sherman Greenberg Development Assistant Foundation of Manitoba draws to a year later, their dream became a reality. -
Finite Combinatorics Combinatoire Finie (Org: Robert Craigen And/Et
Finite Combinatorics Combinatoire finie (Org: Robert Craigen and/et David Gunderson (Manitoba)) WAYNE BROUGHTON, University of British Columbia Okanagan Systems of Parallel Representatives In a finite affine plane of order n, a system of parallel representatives (SPR) is a set of n + 1 lines consisting of exactly one line from each parallel class of the plane. An SPR is tight if no three of its lines are incident on a common point; this is equivalent to a hyperoval in the dual of the associated projective plane of order n. We describe some basic properties of SPR’s and characterize tight SPR’s as those on which a certain sum-of-squares function attains the value zero. We then examine some necessary conditions for an SPR to be minimal with respect to this function, and apply our results to SPR’s in a hypothetical affine plane of order 12. ZOLTAN FUREDI, University of Illinois at Urbana–Champaign Color critical hypergraphs and forbidden configurations A k-uniform hypergraph (V, E) is 3-color-critical if it is not 2-colorable, but for every edge e the hypergraph (V, E − e) is 2-colorable. Lov´asz proved in 1976 that n |E| ≤ k − 1 for a 3-color-critical k-uniform hypergraph with n vertices. Here we give a new algebraic proof and prove a generalization that leads to a sharpening of Sauer’s bound for forb(m, F ), where F is a k-by-` 0, 1-matrix. Joint work with R. Anstee, B. Fleming, and A. Sali. PENNY HAXELL, University of Waterloo On stable paths Let G be a graph with a distinguished vertex d. -
Scientific Workplace· • Mathematical Word Processing • LATEX Typesetting Scientific Word· • Computer Algebra
Scientific WorkPlace· • Mathematical Word Processing • LATEX Typesetting Scientific Word· • Computer Algebra (-l +lr,:znt:,-1 + 2r) ,..,_' '"""""Ke~r~UrN- r o~ r PooiliorK 1.931'J1 Po6'lf ·1.:1l26!.1 Pod:iDnZ 3.881()2 UfW'IICI(JI)( -2.801~ ""'"""U!NecteoZ l!l!iS'11 v~ 0.7815399 Animated plots ln spherical coordln1tes > To make an anlm.ted plot In spherical coordinates 1. Type an expression In thr.. variables . 2 WMh the Insertion poilt In the expression, choose Plot 3D The next exampfe shows a sphere that grows ftom radius 1 to .. Plot 3D Animated + Spherical The Gold Standard for Mathematical Publishing Scientific WorkPlace and Scientific Word Version 5.5 make writing, sharing, and doing mathematics easier. You compose and edit your documents directly on the screen, without having to think in a programming language. A click of a button allows you to typeset your documents in LAT£X. You choose to print with or without LATEX typesetting, or publish on the web. Scientific WorkPlace and Scientific Word enable both professionals and support staff to produce stunning books and articles. Also, the integrated computer algebra system in Scientific WorkPlace enables you to solve and plot equations, animate 20 and 30 plots, rotate, move, and fly through 3D plots, create 3D implicit plots, and more. MuPAD' Pro MuPAD Pro is an integrated and open mathematical problem solving environment for symbolic and numeric computing. Visit our website for details. cK.ichan SOFTWARE , I NC. Visit our website for free trial versions of all our products. www.mackichan.com/notices • Email: info@mac kichan.com • Toll free: 877-724-9673 It@\ A I M S \W ELEGRONIC EDITORIAL BOARD http://www.math.psu.edu/era/ Managing Editors: This electronic-only journal publishes research announcements (up to about 10 Keith Burns journal pages) of significant advances in all branches of mathematics. -
Oral History Interview with Herman Goldstine
An Interview with HERMAN GOLDSTINE OH 18 Conducted by Nancy Stern on 11 August 1980 Charles Babbage Institute The Center for the History of Information Processing University of Minnesota 1 Herman Goldstine Interview 11 August 1980 Abstract Goldstine, associate director of the Institute for Advanced Study (IAS) computer project from 1945 to 1956, discusses his role in the project. He describes the acquisition of funding from the Office of Naval Research, the hiring of staff, and his relationship with John von Neumann. Goldstine explains that von Neumann was responsible for convincing the Institute to sponsor the computer project. Goldstine praises von Neumann's contributions, among which he counts the first logical design of a computer and the concept of stored programming. Goldstine turns next to the relations between the project and one of its funders, the Atomic Energy Commission. He points out the conflict of interest of IAS director Robert Oppenheimer, who chaired the AEC General Advisory Committee, and von Neumann who sat on this committee, when other AEC officials discontinued funding for the project. Goldstine also recounts the problems that arose during the project over patent rights and their resolution. Goldstine concludes by discussing the many visitors to the project and the many computers (Whirlwind, ILLIAC, JOHNNIAC, IBM 70l) modeled after the IAS computer. 2 HERMAN GOLDSTINE INTERVIEW DATE: 11 August 1980 INTERVIEWER: Nancy Stern LOCATION: Princeton, NJ STERN: This is an interview with Herman Goldstine in his home; August 11, 1980. What I'd like to talk about, Herman, for the most part today, is your work with von Neumann at the Institute; that is, the computer project at the Institute; because we've spoken in the past about the Moore School work. -
History of ENIAC
A Short History of the Second American Revolution by Dilys Winegrad and Atsushi Akera (1) Today, the northeast corner of the old Moore School building at the University of Pennsylvania houses a bank of advanced computing workstations maintained by the professional staff of the Computing and Educational Technology Service of Penn's School of Engineering and Applied Science. There, fifty years ago, in a larger room with drab- colored walls and open rafters, stood the first general purpose electronic computer, the Electronic Numerical Integrator And Computer, or ENIAC. It spanned 150 feet in width with twenty banks of flashing lights indicating the results of its computations. ENIAC could add 5,000 numbers or do fourteen 10-digit multiplications in a second-- dead slow by present-day standards, but fast compared with the same task performed on a hand calculator. The fastest mechanical relay computers being operated experimentally at Harvard, Bell Laboratories, and elsewhere could do no more than 15 to 50 additions per second, a full two orders of magnitude slower. By showing that electronic computing circuitry could actually work, ENIAC paved the way for the modern computing industry that stands as its great legacy. ENIAC was by no means the first computer. In 1839, an Englishman Charles Babbage designed and developed the first true mechanical digital computer, which he described as a "difference engine," for solving mathematical problems including simple differential equations. He was assisted in his work by a woman mathematician, Ada Countess Lovelace, a member of the aristocracy and the daughter of Lord Byron. They worked out the mathematics of mechanical computation, which, in turn, led Babbage to design the more ambitious analytical engine.