Remembering Jerry Marsden

Abstract

to his many friends, left us on the 21st of September, 2010, at the age of 68.He leaves behind an applied mathematics school that he created by importing geometric and dynamical systems ideas into diverse applied areas such as numerical analysis, classical applied mathematics, theoretical physics, and engineering.He created strong links between pure and applied mathematics as well as between mathematics and various areas of physics, engineering, and chemistry.His ideas have influenced generations of researchers who have used geometry in their work.Jerry Marsden was involved in the foundations of several areas.For example, the symplectic reduction theorem that he proved together with Alan Weinstein has become so fundamental in any research involving symmetry that it is today inconceivable to work in this field without using it.It has become one of the most cited theorems, often being referred to only by name without even giving a reference, since it is so basic.Jerry helped revive nonholonomic mechanics by introducing symmetry ideas.He used geometric ideas to study partial differential equations in hydrodynamics, elasticity, plasma physics, and relativity.He used symmetry techniques to investigate the nonlinear stability of relative equilibria and bifurcation phenomena associated to them.He has also linked aspects of control theory to symmetry.He used dynamical systems ideas in mission design and collaborated with researchers at the Jet Propulsion Laboratory in Pasadena to produce orbits for the Genesis mission.His ideas to use symplectic and variational methods in numerics greatly contributed to the recent spectacular development of geometric integration.Jerry Marsden had the unusual talent to be able to communicate with scientists in other areas.