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Пределы групповых алгебр для растущих симметрических групп и сплетений
Denote by S(\infty) the infinite symmetric group formed by finitary permutations of the set of natural numbers; this is a countable group. We define its virtual group algebra; it is a completion of the standard group algebra С[S(\infty)]. The virtual group algebra is obtained from the finite-dimensional group algebras C[S(n)] as the result of a limit transition as n\to\infty, where the limit is taken in the so-called tame representations of the group S(\infty). (Note that our virtual group algebra is very different from the C^*-envelope.) We describe the structure of the virtual group algebra, revealing a connection with the degenerate affine Hecke algebras introduced by Drinfeld and Lusztig. Then we extend the results to the wreath products G\wr S(\infty) with arbitrary finite groups G.