The derivation of the BBGKY-hierarchy for the hard sphere system
Date
1989
Authors
Tie, Jingzhi
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Abstract
We study the time evolution of a system of N identical hard spheres in R3 and present a derivation of the BBGKY-hierarchy for the joint distributions of k spheres ( k = l, ... , N ). Previous derivations tacitly assumed that the unknowns had enough regularities for the lower-dimensional integrals appearing in the hierarchy to make sense. A rigorous argument due to Illner & Pulvirenti [7] shows that if the initial measure in phase space is continuous along trajectories and has a suitable decay at space infinity, then a weak version of the BBGKY-hierarchy holds. Here a rigorous proof of the uniqueness of the solution of the weak form is given for a sufficiently regular initial value. The uniqueness leads to the equivalence of the weak and mild versions of the hierarchy.