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Information × Registration Number 0221U000218, 0120U105316 , R & D reports Title It is best to approximate polynomials with constraints and without constraints and a system of subspaces. popup.stage_title Head Shevchuk Ihor О., Доктор фізико-математичних наук Registration Date 03-01-2021 Organization Taras Shevchenko National University of Kyiv popup.description2  The object of research is systems of closed subspaces of Hilbert space, which have the property of inverse best approximation property (IBAP), systems of marginal subspaces. The aim of the work is to obtain different formulas (different from the formulas of PL Combettes and NN Reyes) for solving the problem of the inverse best approximation with the lowest norm, to establish the connection between the property of the inverse best approximation property (IBAP) and Riesz families, to prove that the systems of root subspaces of continuous linear operators possess IBAP, to prove that if the system of closed subspaces of Hilbert space possesses IBAP, then it is a system of eigen subspaces of some continuous operator. Obtain a sufficient condition for a system of marginal subspaces generated by discrete random variables from a certain class to have IBAP. Obtain the necessary condition for a system of marginal subspaces generated by discrete random variables from a certain class to have IBAP. Research methods - methods of functional analysis and operator theory. Product Description popup.authors Motorna Oksana V. Petrova Iryna L. Feshchenko Ivan S. Shteglov Mykyta V. popup.nrat_date 2021-01-03 Close