Berezovskyi O.A.,
V. M. Glushkov Institute of Cybernetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine,
e-mail: berezovskyi@mail.ru.
Abstract. The paper briefly reviews the well-known partial results on the accuracy of dual bounds proposed by N. Z. Shor for quadratic extremal problems. The necessary and sufficient condition for the accuracy of the dual bound for a quadratic problem of general form is presented. Refs: 8 titles.
Keywords: quadratic problem, dual Lagrangian estimate, positive definite matrix, functionally redundant constraints.