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Hard ball systems are completely hyperbolic

Nandor Simányi·Domokos Szász
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Abstract

We consider the system of N (\ge 2) elastically colliding hard balls with masses m_1,..., m_N, radius r, moving uniformly in the flat torus T_L^ν= R^ν/L \cdot Z^ν, ν\ge 2. It is proved here that the relevant Lyapunov exponents of the flow do not vanish for almost every (N+1)-tuple (m_1,...,m_N;L) of the outer geometric parameters.

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Nandor Simányi, Domokos Szász. 1999-01-01. Hard ball systems are completely hyperbolic. https://doi.org/10.2307/121019

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