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We use weighted polynomial approximation to prove the existence of a compact set K with non-empty interior and a function f is dense in the space A(K) of all continuous functions on K that are holomorphic in the interior of K, endowed with…

Complex Variables · Mathematics 2025-06-26 Stéphane Charpentier , Konstantinos Maronikolakis

The notion of the projective hull of a compact set in a complex projective space was introduced by Harvey and Lawson in 2006. In this paper we describe the projective hull by Poletsky sequences of analytic discs, in analogy to the known…

Complex Variables · Mathematics 2013-10-04 Barbara Drinovec Drnovsek , Franc Forstneric

Let $A(K)$ be the algebra of continuous functions on a compact set $K\subset\mathbb C$ which are analytic on the interior of $K$, and $R(K)$ the closure (with the uniform convergence on $K$) of the functions that are analytic on a…

Classical Analysis and ODEs · Mathematics 2019-02-19 Albert Mas

Let $K$ be a non-polar compact subset of $\mathbb{R}$ and $\mu_K$ denote the equilibrium measure of $K$. Furthermore, let $P_n\left(\cdot, \mu_K\right)$ be the $n$-th monic orthogonal polynomial for $\mu_K$. It is shown that…

Classical Analysis and ODEs · Mathematics 2016-03-25 Gökalp Alpan

We give sufficient conditions under which a polyanalytic polynomial of degree $n$ has (i) at least one zero, and (ii) finitely many zeros. In the latter case, we prove that the number of zeros is bounded by $n^2$. We then show that for all…

Complex Variables · Mathematics 2024-06-14 Olivier Sète , Jan Zur

In this paper we generalize Poletsky's classical theorem to a situation where the kernel of Poisson functional is not upper semicontinuous. We give a characterization of thinness of a subset at a point in $\C^n$ in term of analytic discs.

Complex Variables · Mathematics 2014-12-23 Ibrahim K. Djire

We show that, given a family of discs centered at a chord-arc curve, the analytic capacity of a union of arbitrary subsets of these discs (one subset in each disc) is comparable with the sum of their analytic capacities. We show a sort of…

Analysis of PDEs · Mathematics 2014-04-09 Vladimir Eiderman , Alexander Reznikov , Alexander Volberg

We study the possible Hausdorff limits of the Julia sets and filled Julia sets of subsequences of the sequence of dual Chebyshev polynomials of a non-polar compact set K in C and compare such limits to K. Moreover, we prove that the…

For a regular, compact, polynomially convex circled set K in C^2, we construct a sequence of pairs {P_n,Q_n} of homogeneous polynomials in two variables with deg P_n = deg Q_n = n such that the sets K_n: = {(z,w) \in C^2 : |P_n(z,w)| \leq…

Complex Variables · Mathematics 2007-05-23 T. Bloom , N. Levenberg , Yu. Lyubarskii

Let $K$ be a compact set in $\mathbb{C}$, $f$ a function analytic in $\overline{\mathbb{C}}\smallsetminus K$ vanishing at $\infty $. Let $% f\left( z\right) =\sum_{k=0}^{\infty }a_{k}\ z^{-k-1}$ be its Taylor expansion at $\infty $, and…

Complex Variables · Mathematics 2016-09-02 Ozan Günyüz , Vyacheslav Zakharyuta

In 1991, J. Thomson obtained celebrated structural results for $P^t(\mu).$ Later, J. Brennan (2008) generalized Thomson's theorem to $R^t(K,\mu)$ when the diameters of the components of $\mathbb C\setminus K$ are bounded below. The results…

Functional Analysis · Mathematics 2022-12-13 John B. Conway , Liming Yang

Let $K\subset\mathbb{C}$ be non-polar, compact and polynomially convex. We study the limits of equilibrium measures on preimages of compact sets, under $K$-regular sequences of polynomials, that center on $K$ and under the sequences of…

Dynamical Systems · Mathematics 2025-12-12 Christian Henriksen , Carsten Lunde Petersen , Eva Uhre

We construct an essential extension of $\mathcal K(\ell_2({\mathfrak{c}}))$ by $\mathcal K(\ell_2)$, where ${\mathfrak{c}}$ denotes the cardinality of continuum, i.e., a $C^*$-algebra $\mathcal A\subseteq \mathcal B(\ell_2)$ satisfying the…

Operator Algebras · Mathematics 2018-09-05 Saeed Ghasemi , Piotr Koszmider

We use our disc formula for the Siciak-Zahariuta extremal function to characterize the polynomial hull of a connected compact subset of complex affine space in terms of analytic discs.

Complex Variables · Mathematics 2007-05-23 Finnur Larusson , Ragnar Sigurdsson

We study Widom factors for (a) monic orthogonal polynomials in $L^2$ with respect to the equilibrium measure of a compact set $K\subset\mathbb{R}$ and (b) residual polynomials normalized at an exterior point. Using weakly equilibrium Cantor…

Complex Variables · Mathematics 2025-08-22 Gökalp Alpan

We present a proof architecture for \(P \neq NP\) based on an upper--lower clash in polytime-capped conditional description length. We construct an efficiently samplable family of SAT instances \(Y\) such that every satisfying witness for…

Computational Complexity · Computer Science 2026-04-24 Ben Goertzel

Let $X$ be a smooth irreducible quasi-projective algebraic variety over a number field $K$. Suppose $X$ is equipped with a $p$-adic \'{e}tale local system compatible with an admissible graded-polarized variation of mixed Hodge structures on…

Number Theory · Mathematics 2025-08-15 Kenneth Chung Tak Chiu

The existence of a nontrivial polynomially convex hull with every point a one-point Gleason part and with no nonzero bounded point derivations is established. This strengthens the \hbox{celebrated} result of Stolzenberg that there exists a…

Complex Variables · Mathematics 2016-05-16 Brian J. Cole , Swarup N. Ghosh , Alexander J. Izzo

Extensions of the notions of polynomially and rationally convex hulls are introduced. Using these notions, a generalization of a result of Duval and Levenberg on polynomially convex hulls containing no analytic discs is presented. As a…

Complex Variables · Mathematics 2019-02-26 Alexander J. Izzo

Using a recent result of L\'arusson and Poletsky regarding plurisubharmonic subextensions we prove a disc formula for the quasiplurisubharmonic global extremal function for domains in complex projective space. As a corollary we get a…

Complex Variables · Mathematics 2013-05-22 Benedikt Steinar Magnusson