title: Billiard in a barrel.
abstract: Orbits in the three-dimensional billiard of the form of a truncated ellipsoid ("barrel") are studied both analytically and numerically. A special form of mapping is proposed to get the expression for Kolmogorov-Sinai entropy, and the transition from strong chaos to weak chaos is obtained.
authors.affiliation: Courant Institute of Mathematical Sciences, New York University, New York, New York 10012.
authors.forename: George M.
authors.initials: GM
authors.lastname: Zaslavsky
authors.forename: H. R.
authors.initials: HR
authors.lastname: Strauss