Volume 11, Number 2 THE NEWSLETTER OF THE MATHEMATICAL ASSOCIATION OF AMERICA April 1991 At the Frontiers of Science: Students Welcome The NAS Throws a Symposium at the New Orono Mathfest Peter L. Renz National meetings can make a difference in the lives of students. In a letter that Diane L. Herrmann, now a member of the Depart­ Blackboard presentations with a few slides have given way to vue­ ment of Mathematics at the University of Chicago, wrote to MAA graphs and computer images. The machines range from modest representatives before the January 1991 Annual Meeting in San work stations to super computers. This was the style at the Na­ Francisco, she explained: tional Academy of Science's (NAS) second annual "Frontiers of Science Symposium," held at the Arnold and Mabel Beckman Cen­ "When I was in college, we piled as many of us as would fit in a van ter in Irvine, California, 1-3 November 1990. Mathematics was in or two and drove across Pennsylvania in January to go to the MAA evidence, not only in the dynamical systems sessions organized by meeting in Washington. We shared gas money, slept as many as William P. Thurston, but in most of the other nine sessions as well. possible to a hotel room, and ate at cheap restaurants. We went to a few talks, when we understood words in the titles. We spent time Roughly 50 out of 100 scientists attending had obvious mathemati­ off our campus with faculty members who shared with us stories of cal sides to their professional work-the exceptions being in biology their own student days. We even went to the business meeting for or chemistry. But Eric Lander of the Whitehead Institute for Biomed­ a while. For a few days we found ourselves in the company of all ical Research, mathematician and organizer of the session on gene these hundreds of mathematicians. It was an amazing time." regulation, said that mathematics and computers are essential in these areas for sequencing and pattern recognition: Now the MAA Committee on Student Chapters and Pi Mu Epsilon (PME) are rolling out the red carpet once again to welcome students To attend was to think about fundamentals of one's own field and to the Summer Meeting that takes place from 8-10 August 1991, of the fields of others. Why? Ask yourself how you would explain in Orono, Maine. To bring students together during the meetings, some piece of mathematics to molecular geneticists. You get the PME and the MAA will host a reception for students on Friday idea. Imagine listening to a like explanation by an organic chemist. evening. Throughout the meeting, the Student Hospitality Center Concentrate this into twenty hours of scientific sessions with seven­ will provide a place where students can get acquainted with each teen hours scheduled for coffee breaks, meals, and informal com­ other and where they can obtain meeting information from members (Frontiers continues on page two.) (Welcome continues on page seven.) Inside This Issue State Coalitions: Collaboration to Improve Mathematics Education 4 COMET Releases A Call for Change: Recommendations on the Mathematical Preparation of Teachers of Mathematics 5 Association Seeks Visiting Mathematicians for Its Washington, DC Headquarters 5 1990 Meritorious Service Awards 6 and 7 Study Ancient Greek Mathematics in Greece! 7 Two-Thirds Toward Its Goal: The MAA Mathematical Center Building Fund _ 8 Board Actions in San Francisco 32 SUMMA Seeks Proposals for Its Small Grants for Development of Mathematics Intervention Projects 32 Mathematician Jean E. Taylor of Rutgers University and physicist CENTER SECTION: Michael Widom of Carnegie-Mellon University discuss the x-ray Exposition, Explanation, and Examples? spectra of aperiodic arrangements of atoms during the National The 1991 Summer Meeting in Orono, Maine 9-31 Academy of Science's Frontiers of Science Symposium. 2 FOCUS April 1991 (Frontiers continued from front page.) from dynamo action in three convection rolls in the Earth's core munication over two and one-half days and the picture is complete. oriented in the direction of the earth's axis and tangent to the inner The spirit was open; areas of ignorance were discussed frankly, core. Fluid velocities are a surprising 20 kilometers per year. and detailed, recent knowledge was evident. What we know about the movement of crustal plates above hot In order of presentation the sessions were: atmospheric science spots in the mantle comes from analysis of the rocks and corals of and air pollution, dynamical systems, gene regulation and transcrip­ islands and submerged sea mounts in the Pacific. The coral reefs, tion, magnetic resonance imaging, galaxies and the distribution of which can only grow at certain depths, tell a good deal. Marcia matter in the universe, the physics of quasicrystals and high temper­ McNutt of MIT spoke of this work. ature superconductors, how the earth works, unexpected scientific computing, neural networks, and photosynthesis. Michael Gurnis of the University of Michigan showed how advances and retreats of continental coastlines can be simulated by treating I will sketch the earth science session, which was typical, and cover the continents as an isostatic "scum" floating on the mantle. The other areas as space allows, emphasizing mathematical problems model was simplified, the details were suppressed, but the video and methods. was convincing-suggestive of the evolution of real continents. Danger, Earth at Work David Stevenson of Caltech began his The mathematical tools used included analysis of fields by spheri­ talk, "How the Earth Works," remarking, "Ignorance is more inter­ cal harmonics, partial differential equations and their numerical so­ esting than knowledge." He discussed problems of plate tectonics lutions, and visual representation of the results. (plates aren't completely rigid), mantle convection (difficult to mea­ sure or model, unknowns include the importance of vulcanism and Chaos at Work? John Hamel Hubbard of Cornell University led melting, just one of the complexities of the mantle interacting with off on dynamical systems. He raised philosophical and mathemat­ crustal plates), and geomagnetism (a dynamic phenomenon). ical questions. Is the "butterfly effect" real? Is the weather in New York significantly affected by minor disturbances such as a butter­ The search for understanding gives life to our subjects. Hence fly flapping its wings in Japan six months earlier? Is the quantum Stevenson's interest in ignorance. General mechanisms are uncertainty of Heisenberg magnified by the expansive dynamics known. The earth is a heat engine: heat from the core drives of an unstable system (a pencil balanced on its tip) to make the mantle convection which in turn drives the crustal plates. Some eventual outcome totally unpredictable? Is the unrolling of events details are known: the variations of the earth's magnetic field over deterministic but governed by a script that we cannot read in infi­ several hundred years, the movements of the crustal plates, and nite detail (because of quantum limitations on measurement) or is activity of volcanic hot spots over hundreds of millions of years. Yet it nondeterministic with some random element (free will)? full understanding remains elusive. How to address such questions? We find models in the chaotic Jeremy Bloxham of Harvard University described his analysis of dynamics of simple systems that can be exquisitely sensitive to changes in the earth's magnetic field based on magnetic naviga­ both initial conditions and parameters. These systems can show tional surveys extending back over 300 years. The changes arise exponential divergence under perturbation. For the weather mod­ els used by the French Atmospheric Sciences Institute, Hubbard gave an estimate of two to three days for the doubling time of perturbations, about right to make the butterfly effect real. Roughly the same number of doublings would make the "balanced" quantum pencil fall in a few seconds. But a physicist in the audience pointed out that, for the pencil, perturbations from photons will "collapse the wave packet" and settle the fate of the pencil before the blow up of Heisenberg uncertainty did the job. Audience involvement here was a sign of a successful speaker. Hubbard's related mathematical question arises from looking at the dynamics of a system like xn+l = 10xn(mod 1), where Xo is a real number between 0 and 1. This drops the leading digit of X n and shifts the other digits one place left. A random choice for Xo should give random leading digits for the x k- Think of these leading digits as the observables of the process, the rest of x k being be­ yond our quantum limit of observation. Easily written down seeds, xo, give nonrandom sequences of observables, these being of little interest. Hubbard suggests that for reasonable seeds, xo, looking at Xn+l = 2x; - 1 will yield as random a string of observables as you might wish. This makes Xk = cos(2kxo), and for most ra­ tional choices for Xo the angles 2kXo should fall randomly around the circle. Is this a short program capable of generating pseudo­ random digits or numbers as random as one might wish? To prove or refute this assertion, one must deal with problems of machine precision and reasonable definitions of pseudorandomness. Note Starting from a decapod seed and adding only those tiles forced by that 1/2 is not a good choice for x 0 . their local rules, Paul Steinhardt and Kevin Ingersent, his student, generated this rapidly growing Penrose tiling of the plane. The Hubbard suggested that interesting things (Julia sets, the Mandel­ five-fold rotational symmetry about the decapod imperfection is brot set, living things) are specified by exceptionally short programs evident. Steinhardt and Ingersent conjecture that these rapidly (quadratic formulas, genetic codes).