Ralph Abraham

Ralph H. Abraham (born July 4, 1936, Burlington, Vermont) is an American mathematician. He has been a member of the mathematics department at the University of California, Santa Cruz since 1968... Abraham has been involved in the development of dynamical systems theory in the 1960s and 1970s. He has been a consultant on Chaos Theory and its applications in numerous fields, such as medical physiology, ecology, mathematical economics, psychotherapy, etc. https://en.wikipedia.org/wiki/Ralph_Abraham