New monograph of the head of “Nonharmonic-analysis” department of IMM ANAS, corr. Member of ANAS, prof. Bilal Bilalov’s “Some approximation problems” was published.

The monograph contains some aspects of approximation and bases theory. Main notion and facts of approximation theory in the cases of finite and infinite spaces were given. Some generalizations of Tensor products, bilinear mappings, subspaces, etc. were introduced.

Main theoretical aspects of frames and perturbed frames theory were also represented.

The book published in “Elm” publishing house consists of 390 pages. The book may be used by higher course students, doctoral students and specialists on approximation theory, spectral theory of differential operators and so on.