Systems theory to social sciences (see David Easton's seminal development of the "political system" as an analytical construct), the original theorists explored the implications of twentieth century advances in terms of systems. People have studied subjects like complexity, self-organization, connectionism and adaptive systems in the 1940s and 1950s. In fields like cybernetics, researchers such as Norbert Wiener, William Ross Ashby, John von Neumann and Heinz von Foerster, examined complex systems mathematically. John von Neumann discovered cellular automata and self-reproducing systems, again with only pencil and paper. Aleksandr Lyapunov and Jules Henri Poincaré worked on the foundations of chaos theory without any computer
Giovanni Forni (mathematician) American Mathematical Society. Giovanni Forni (mathematician) Giovanni Forni is an Italian mathematician at the University of Maryland known for his research in dynamical systems. After graduating from the University of Bologna in 1989, he obtained his PhD in 1993 from Princeton University, under the supervision of John Mather. He was an invited speaker at the 2002 International Congress of Mathematicians in Beijing. For his work on solutions of cohomological equations for flows on surfaces, and on the Kontsevich–Zorich conjecture concerning deviation of ergodic averages, he was awarded the 2008 Michael Brin Prize in Dynamical Systems. In 2012, he became a