Richard Palais and Luc Benard
Mathematicians have used advances in the graphic arts to improve how they display mathematical concepts in their teaching and research going back to that ancient “upgrade” from drawing diagrams in sand to incising them in clay tablets. So it is no surprise that the paradigm changing modern technology of computers has provided spectacular new possibilities for visualizing ever more complex mathematical objects and processes. The authors of this gallery explore these objects, using among others 3D-XplorMath, a math visualization program designed to exploit fully this new technology. It is in effect a virtual math museum with an intuitive user interface that allows even non-mathematicians to take advantage of the new graphic possibilities to experience the visual beauty inherent in many different fields of mathematics.
Lyapunov Play
Mario Markus of the Max Planck Institute of Molecular Physiology has used dynamical systems to study the evolution of animal populations - the change over time of food, fertility, size, etc. - with dynamics requiring the ability of reproduction to alternate quasi-periodically between two values. Such systems can show both a stable cycle and chaotic evolution depending on the fertility ability. Stability or chaos can be analysed by computing the so-called Lyapunov exponent. (Lyapunov was a Russian mathematician living at the end of the 19th century)
Markus-Lyapunov images are colour mappings of the Lyapunov exponent versus fertility, along horizontal and vertical axes. Only the stability domain is plotted; here, chaos (i. e. positive Lyapunov exponent) is rendered in dark blue. As the exponent goes from 0 to minus infinity, shades range from light to dark. At zero, the chaos threshold, the colour suddenly jumps from dark blue to a lighter shade. There is clearly much that is arbitrary in this colour mapping, and this gives an opportunity for choices based on aesthetic considerations. The picture consists of seven original Markus-Lyapunov pictures which were rebuilt and superimposed.