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We study the unilateral shift (of arbitrary countable multiplicity) as a Hilbert module over the disc algebra and the associated extension groups. In relation with the problem of determining whether this module is projective, we consider a…

Operator Algebras · Mathematics 2014-05-23 Raphaël Clouâtre

We establish plurisubharmonicity of the envelope of Poisson and Lelong functionals on almost complex manifolds. That is, we generalize the corresponding results for complex manifolds and almost complex manifolds of complex dimension two. We…

Complex Variables · Mathematics 2015-07-27 Florian Bertrand , Uros Kuzman

Let T be the unit circle in the complex plane C. This paper proves the existence of analytic structure in a compact subset K of T X C^n, where K has so-called "lineally convex" or "hypoconvex" fibers over T. It also addresses a related…

Complex Variables · Mathematics 2007-05-23 Marshall A. Whittlesey

Let A be a closed polar subset of a domain D in the complex plane C. We give a complete description of the pluripolar hull in D X C of the graph of a holomorphic function defined on D A. To achieve this, we prove for pluriharmonic measure…

Complex Variables · Mathematics 2007-05-23 Armen Edigarian , Jan Wiegerinck

We obtain Schwarz-Pick lemma for $(\alpha, \beta)$-harmonic functions u in the disc, where $\alpha$ and $\beta$ are complex parameters satisfying $\Re \alpha + \Re \beta > -1$. We prove sharp estimate of derivative at the origin for such…

Complex Variables · Mathematics 2023-12-13 Miloš Arsenović , Jelena Gajić

This paper is a second part of our study of the Discrete Polyharmonic Cubature Formulas on the disc. It completes our study and provides a satisfactory cubature formula in terms of precision and number of evaluation points (coefficient of…

Numerical Analysis · Mathematics 2015-09-02 O. Kounchev , H. Render

We study weighted $H^\infty$ spaces of analytic functions on the open unit disc in the case of non-doubling weights, which decrease rapidly with respect to the boundary distance. We characterize the solid hulls of such spaces and give quite…

Functional Analysis · Mathematics 2017-02-02 José Bonet , Jari Taskinen

It is shown that if $A$ is a unital commutative Banach algebra with a dense set of invertible elements, then the maximal ideal space of $A$ contains no compact, locally connected, simply coconnected subspace of topological dimension $\geq…

Complex Variables · Mathematics 2018-07-31 Alexander J. Izzo

We prove that if a compact set E in complex Euclidean space is contained in an arc J, then there is a choice of J whose polynomial hull is the union of J and the polynomial hull of E. This strengthens an earlier result of the author. We…

Complex Variables · Mathematics 2021-06-21 Alexander J. Izzo

This paper is devoted to Riemann-Hilbert problems with constraints. We obtain results characterizing the existence of solutions as well as the dimension of the solution space in terms of certain indices. As an application, we show how such…

Complex Variables · Mathematics 2018-08-22 Florian Bertrand , Giuseppe Della Sala

Let X be a complex manifold and c a simple closed curve in X. We address the question: What conditions on c ensure the existence of a 1-dimensional complex subvariety V with boundary c in X. When X = C^n, an answer to this question involves…

Complex Variables · Mathematics 2008-08-21 H. Blaine Lawson , John Wermer

The aim of this paper is to describe explicitly the poles of the meromorphic continuation of the Igusa local zeta function associated to several polynomials. Using resolution of singularities is possible to express the Igusa's local zeta…

Number Theory · Mathematics 2007-05-23 W. A. Zuniga-Galindo

Examples by Poletsky and the author and by Zwonek show the existence nowhere extendable holomorphic functions with the property that the pluripolar hull of their graphs is much larger than the graph of the respective functions and contains…

Complex Variables · Mathematics 2022-10-05 Jan Wiegerinck

In 1962 J. Siciak introduced polynomial extremal function. The Siciak extremal function is one of the most important tool to investigate derivatives of polynomials. W. Ple\'sniak in the circle of papers (most important joint with W.…

Complex Variables · Mathematics 2018-08-07 Mirosław Baran , Leokadia Białas-Cież

We prove a classification of additive polynomial superfunctors, which allows us to compute some extensions of a superfunctor of the form $F \circ A$ where $F$ is a classical polynomial functor and $A$ is additive. We get a formula which…

Algebraic Topology · Mathematics 2022-02-01 Iacopo Giordano

This paper develops a correspondence relating convex hulls of fractional functions with those of polynomial functions over the same domain. Using this result, we develop a number of new reformulations and relaxations for fractional…

Optimization and Control · Mathematics 2024-06-18 Taotao He , Siyue Liu , Mohit Tawarmalani

We compute the extremal plurisubharmonic function of the real torus viewed as a compact subset of its natural algebraic complexification.

Complex Variables · Mathematics 2018-11-08 Federico Piazzon

We establish the existence of liftings into discrete subspaces of $\mathbf{H}(\mathrm{div})$ of piecewise polynomial data on locally refined simplicial partitions of polygonal/polyhedral domains. Our liftings are robust with respect to the…

Numerical Analysis · Mathematics 2025-01-29 Alexandre Ern , Iain Smears , Martin Vohralík

We study boundary properties of plurisubharmonic functions near real submanifolds of almost complex manifolds.

Complex Variables · Mathematics 2020-08-26 Alexandre Sukhov

We construct a connected, compact set $K \subset \mathbb{C}^2$ with the following property: there exist points $p \in \hat{K} \setminus K$ such that there does not exist a sequence $\{A_\nu\}$ of analytic sets $A_\nu \subset\subset…

Complex Variables · Mathematics 2025-07-23 Tobias Harz