On soft billiard systems
It is shown that soft billiard systems with parameters (U,R) [as introduced by \textit{P. R. Baldwin}, Physica D 29, No.3, 321-342 (1988; Zbl 0644.58010)] have positive Lyapunov exponent in the complement of \(B=\{(U,R)|\) \(1-(1-2R)^{-2}<U<0\}.\) Inside B, the soft billiard had previously been shown by Baldwin to be generically non-ergodic.
scientific article; zbMATH DE number 4143097
scientific article