Geodesic
Operators of Hankel type
Czechoslovak Mathematical Journal, Tome 56 (2006) no. 4, pp. 1147-1163 Cet article a éte moissonné depuis la source Czech Digital Mathematics Library

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Hankel operators and their symbols, as generalized by V. Pták and P. Vrbová, are considered. The present note provides a parametric labeling of all the Hankel symbols of a given Hankel operator $X$ by means of Schur class functions. The result includes uniqueness criteria and a Schur like formula. As a by-product, a new proof of the existence of Hankel symbols is obtained. The proof is established by associating to the data of the problem a suitable isometry $V$ so that there is a bijective correspondence between the symbols of $X$ and the minimal unitary extensions of $V$.
Hankel operators and their symbols, as generalized by V. Pták and P. Vrbová, are considered. The present note provides a parametric labeling of all the Hankel symbols of a given Hankel operator $X$ by means of Schur class functions. The result includes uniqueness criteria and a Schur like formula. As a by-product, a new proof of the existence of Hankel symbols is obtained. The proof is established by associating to the data of the problem a suitable isometry $V$ so that there is a bijective correspondence between the symbols of $X$ and the minimal unitary extensions of $V$.
Classification : 47A20, 47B35
Keywords: Hankel operators; Hankel symbols 
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     title = {Operators of {Hankel} type},
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Bermudo, S.; Marcantognini, S. A. M.; Morán, M. D. Operators of Hankel type. Czechoslovak Mathematical Journal, Tome 56 (2006) no. 4, pp. 1147-1163. http://geodesic.mathdoc.fr/item/CMJ_2006_56_4_a5/

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