Focusing on settings that are consistent with semi-flows defined by
dissipative parabolic PDEs, I will discuss some first steps toward
building a dynamical systems theory, in particular a theory of chaotic
systems, for maps and semi-flows in Hilbert and Banach spaces.
I will survey known results and present recent progress, including
theorems on Lyapunov exponents, periodic solutions and horseshoes,
entropy formula and SRB measures, and a notion of “almost every”
initial condition that is natural to the underlying dynamics. Technical
differences between finite and infinite dimensions will also be discussed