Geodesic
Limit behavior of Weyl coefficients
Algebra i analiz, Tome 33 (2021) no. 5, pp. 153-175.

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The sets of radial or nontangential limit points towards $i\infty$ of a Nevanlinna function $q$ are studied. Given a nonempty, closed, and connected subset $\mathcal{L}$ of $\overline{\mathbb C_+}$, a Hamiltonian $H$ is constructed explicitly such that the radial and outer angular cluster sets towards $i\infty$ of the Weyl coefficient $q_H$ are both equal to $\mathcal{L}$. The method is based on a study of the continuous group action of rescaling operators on the set of all Hamiltonians.
Keywords: Weyl coefficient, canonical system, cluster set, Nevanlinna function. 
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R. Pruckner; H. Woracek. Limit behavior of Weyl coefficients. Algebra i analiz, Tome 33 (2021) no. 5, pp. 153-175. http://geodesic.mathdoc.fr/item/AA_2021_33_5_a4/

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