000			02262nam a22003377a 4500
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020			_a9783034877145
040			_aNISER LIBRARY _beng _cNISER LIBRARY
041			_aEnglish
082			_a517.518.85 _bFOI-C
100			_aFoias, Ciprian
245			_aCommutant lifting approach to interpolation problems
260			_aSwitzerland : _bSpringer Basel AG, _c1990.
300			_axxiii, 632p. : _c24 cm.
490			_aOperator theory, advances and applications ; _vv. 44
504			_aIncludes bibliographical references and index.
520			_aClassical H~ interpolation theory was conceived at the beginning of the century by C. Caratheodory, L. Fejer and I. Schur. The basic method, due to Schur, in solving these problems consists in applying the Möbius transform to peel off the data. In 1967, D. Sarason encompassed these classical interpolation problems in a representation theorem of operators commuting with special contractions. Shortly after that, in 1968, B. Sz. Nagy and C. Foias obtained a purely geometrical extension of Sarason's results. Actually, their result states that operators intertwining restrictions of co-isometries can be extended, by preserving their norm, to operators intertwining these co-isometries; starring with R.G. Douglas, P.S. Muhly and C. Pearcy, this is referred to as the commutant lifting theorem. In 1957, Z. Nehari considered an L ~ interpolation problern which in turn encompassed the same classical interpolation problems, as well as the computation of the distance of a function f in L ~ to H~. At about the sametime as Sarason's work, V.M.
650			_aInterpolation.
650			_aLifting theory.
650			_aBoundary element method
650			_aControl theory
650			_aHilbert space
650			_aMathematical programming
650			_aMatrices
700			_aFrazho, Arthur E.
856			_3Table of contents _uhttps://link.springer.com/book/10.1007/978-3-0348-7712-1#toc
856			_3Reviews _uhttps://www.goodreads.com/book/show/3540544-the-commutant-lifting-approach-to-interpolation-problems?from_search=true&from_srp=true&qid=7PJpkQC0Gv&rank=2#CommunityReviews
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