Introduction to Koopman operator theory of dynamical systems

These notes provide a brief introduction to the theory of the Koopman operator. This theory is an alternative operator-theoretic formalism of dynamical systems theory which offers great utility in analysis and control of nonlinear and high-dimensional systems using data. The style of presentation is informal, and a detailed list of references is given at the end which contain rigorous mathematical treatments as well as a variety of applications to physics and engineering problems.