Dear All, We are delighted to present the MaPSS Seminar topic of Monday 09/10; please see the abstract below. **This Semester the Seminar will always run on Monday, at 5:00pm in 535A** Following the talk, there will be pizza on offer. Speaker: John Wormell (Sydney University) Title: A user’s guide to chaotic systems Abstract: Chaotic behaviour is common in real-world dynamical systems, but chaotic systems are notoriously "impossible to predict". But nevertheless, what useful things can you say about the (long-term) behaviour of a chaotic system? The answer is largely in and around ergodic theory. We introduce some statistical properties generally possessed by chaotic systems, sketch how people try to prove these properties exist, and discuss how they can be used to form a useful dynamical picture of a given system. Supervisors, please encourage your students to attend. Thanks, MaPSS Organizers