http://hdl.handle.net/123456789/26 Wed, 15 Apr 2026 22:48:20 GMT 2026-04-15T22:48:20Z http://hdl.handle.net/123456789/36 Metrizable ball structures Protasov, I.V. A ball structure is a triple (X, P,B), where X, P are nonempty sets and, for any x ∈ X, α ∈ P, B(x, α) is a subset of X, x ∈ B(x, α), which is called a ball of radius α around x. We characterize up to isomorphism the ball structures related to the metric spaces of different types and groups. Tue, 24 Sep 2002 00:00:00 GMT http://hdl.handle.net/123456789/36 2002-09-24T00:00:00Z http://hdl.handle.net/123456789/35 Virtual endomorphisms of groups Nekrashevych, Volodymyr Mon, 21 Oct 2002 00:00:00 GMT http://hdl.handle.net/123456789/35 2002-10-21T00:00:00Z http://hdl.handle.net/123456789/34 On the finite state automorphism group of a rooted tree Lavrenyuk, Yaroslav The normalizer of the finite state automorphism group of a rooted homogeneous tree in the full automorphism group of this tree was investigated. General form of elements in the nor- malizer was obtained and countability of the normalizer was proved. Mon, 23 Sep 2002 00:00:00 GMT http://hdl.handle.net/123456789/34 2002-09-23T00:00:00Z http://hdl.handle.net/123456789/33 Radical theory in BCH-algebras Dudek, W. A.; Jun, Y. B. Fri, 10 May 2002 00:00:00 GMT http://hdl.handle.net/123456789/33 2002-05-10T00:00:00Z