V. Kovač

activity

20102026

most citedOn the combined use of GW approximation and cumulant expansion in the calculations of quasiparticle spectra: The paradigm of Si valence bands

50 citations · 289 across the 33 of their papers we have counts for

collaborators

34 papers

math-ph2026

A converse to generalized Runcorn's theorem

Vjekoslav Kovač, Ivica Smolić

We study an inverse problem for generalized Runcorn's theorem motivated by an apparent paradox of lunar magnetism. In mathematical terms, we characterize square-integrable complex…

math.NT2024★ 1 cited

On several irrationality problems for Ahmes series

Vjekoslav Kovač, Terence Tao

Using basic tools of mathematical analysis and elementary probability theory we address several problems on the irrationality of series of distinct unit fractions, $\sum_{k} 1/ a_{k}$ .…

math.CA2023

Large dilates of hypercube graphs in the plane

Vjekoslav Kovač, Bruno Predojević

We study a distance graph $Γ_{n}$ that is isomorphic to the $1$ -skeleton of an $n$ -dimensional unit hypercube. We show that every measurable set of positive upper Banach density in t…

math.CA2023

A strong-type Furstenberg-Sárközy theorem for sets of positive measure

Polona Durcik, Vjekoslav Kovač, Mario Stipčić

For every $β \in (0, \infty)$ , $β \neq = 1$ we prove that a positive measure subset $A$ of the unit square contains a point $(x_{0}, y_{0})$ such that $A$ nontrivially intersects curves $y-y_…

math.CA2022

Multi-parameter maximal Fourier restriction

Aleksandar Bulj, Vjekoslav Kovač

The main result of this note is the strengthening of a quite arbitrary a priori Fourier restriction estimate to a multi-parameter maximal estimate of the same type. This allows us…

math.CA2022★ 4 cited

On binomial sums, additive energies, and lazy random walks

Vjekoslav Kovač

We establish a sharp estimate for $k$ -additive energies of subsets of the discrete hypercube conjectured by de Dios Pont, Greenfeld, Ivanisvili, and Madrid in arXiv:2112.09352, whi…

math.CA2021★ 2 cited

Sharp $L^{p}$ estimates of powers of the complex Riesz transform

Andrea Carbonaro, Oliver Dragičević, Vjekoslav Kovač

Let $R_{1, 2}$ be scalar Riesz transforms on $R^{2}$ . We prove that the $L^{p}$ norms of $k$ -th powers of the operator $R_{2} + i R_{1}$ behave exactly as $∣ k ∣^{1 - 2/ p} p$ , uniformly in…

math.AP2021★ 1 cited

Trilinear embedding for divergence-form operators with complex coefficients

Andrea Carbonaro, Oliver Dragičević, Vjekoslav Kovač +1

We prove a dimension-free $L^{p} (Ω) \times L^{q} (Ω) \times L^{r} (Ω) \to L^{1} (Ω \times (0, \infty))$ embedding for triples of elliptic operators in divergence form with complex coeffici…

math.DS2020★ 4 cited

Pointwise convergence of certain continuous-time double ergodic averages

Michael Christ, Polona Durcik, Vjekoslav Kovač +1

We prove a.e. convergence of continuous-time quadratic averages with respect to two commuting $R$ -actions, coming from a single jointly measurable measure-preserving $\mat…

math.CA2020★ 6 cited

Density theorems for anisotropic point configurations

Vjekoslav Kovač

Several results in the existing literature establish Euclidean density theorems of the following strong type. These results claim that every set of positive upper Banach density in…

math.CA2020★ 3 cited

The density of sets containing large similar copies of finite sets

Kenneth Falconer, Vjekoslav Kovač, Alexia Yavicoli

We prove that if $E \subseteq R^{d}$ ( $d \geq 2$ ) is a Lebesgue-measurable set with density larger than $\frac{n - 2}{n - 1}$ , then $E$ contains similar copies of every $n$ -point…

math.PR2020★ 2 cited

Convergence of ergodic-martingale paraproducts

Vjekoslav Kovač, Mario Stipčić

In this note we introduce a sequence of bilinear operators that unify ergodic averages and backward martingales in a nontrivial way. We establish its convergence in a range of $L^p…

math.CA2020★ 9 cited

A Szemerédi-type theorem for subsets of the unit cube

Polona Durcik, Vjekoslav Kovač

We investigate gaps of $n$ -term arithmetic progressions $x, x + y, \dots, x + (n - 1) y$ inside a positive measure subset $A$ of the unit cube $[0, 1]^{d}$ . If lengths of their gaps $y$ are…

math.CA2018★ 10 cited

Fourier restriction implies maximal and variational Fourier restriction

Vjekoslav Kovač

We give an abstract argument that an a priori Fourier restriction estimate for a certain choice of exponents automatically implies maximal and variational Fourier restriction estim…

math.CA2018★ 9 cited

A variational restriction theorem

Vjekoslav Kovač, Diogo Oliveira e Silva

We establish variational estimates related to the problem of restricting the Fourier transform of a three-dimensional function to the two-dimensional Euclidean sphere. At the same…

math.CO2018★ 8 cited

Boxes, extended boxes, and sets of positive upper density in the Euclidean space

Polona Durcik, Vjekoslav Kovač

We prove that sets with positive upper Banach density in sufficiently large dimensions contain congruent copies of all sufficiently large dilates of three specific higher-dimension…

math.FA2017★ 1 cited

Characterizations of democratic systems of translates on locally compact abelian groups

Vjekoslav Kovač, Hrvoje Šikić

We present characterizations of democratic property for systems of translates on a general locally compact abelian group, along a lattice in that group. That way we generalize the…

math.CA2017★ 2 cited

A sharp nonlinear Hausdorff-Young inequality for small potentials

Vjekoslav Kovač, Diogo Oliveira e Silva, Jelena Rupčić

The nonlinear Hausdorff-Young inequality follows from the work of Christ and Kiselev. Later Muscalu, Tao, and Thiele asked if the constants can be chosen independently of the expon…

math.CO2016★ 17 cited

On side lengths of corners in positive density subsets of the Euclidean space

Polona Durcik, Vjekoslav Kovač, Luka Rimanić

We generalize a result by Cook, Magyar, and Pramanik [3] on three-term arithmetic progressions in subsets of $R^{d}$ to corners in subsets of $\mathbb{R}^d\times\mathbb{R}^d…

math.PR2016★ 3 cited

Bellman functions and $L^{p}$ estimates for paraproducts

Vjekoslav Kovač, Kristina Ana Škreb

We give an explicit formula for one possible Bellman function associated with the $L^{p}$ boundedness of dyadic paraproducts regarded as bilinear operators or trilinear forms. Then w…

math.CA2016★ 11 cited

Power-type cancellation for the simplex Hilbert transform

Polona Durcik, Vjekoslav Kovač, Christoph Thiele

We prove $L^{p}$ bounds for the truncated simplex Hilbert transform which grow with a power less than one of the truncation range in the logarithmic scale.

cond-mat.mtrl-sci2016★ 50 cited

On the combined use of GW approximation and cumulant expansion in the calculations of quasiparticle spectra: The paradigm of Si valence bands

Branko Gumhalter, Vjekoslav Kovač, Fabio Caruso +2

Since the earliest implementations of the various GW approximations and cumulant expansion in the calculations of quasiparticle propagators and spectra, several attempts have been…

math.DS2016★ 22 cited

Norm-variation of ergodic averages with respect to two commuting transformations

Polona Durcik, Vjekoslav Kovač, Kristina Ana Škreb +1

We study double ergodic averages with respect to two general commuting transformations and establish a sharp quantitative result on their convergence in the norm. We approach the p…

math.CA2015★ 2 cited

On a trilinear singular integral form with determinantal kernel

Philip Gressman, Danqing He, Vjekoslav Kovač +3

We study a trilinear singular integral form acting on two-dimensional functions and possessing invariances under arbitrary matrix dilations and linear modulations. One part of the…

A converse to generalized Runcorn's theorem

On several irrationality problems for Ahmes series

Large dilates of hypercube graphs in the plane

A strong-type Furstenberg-Sárközy theorem for sets of positive measure

Multi-parameter maximal Fourier restriction

On binomial sums, additive energies, and lazy random walks

Sharp Lp estimates of powers of the complex Riesz transform

Trilinear embedding for divergence-form operators with complex coefficients

Pointwise convergence of certain continuous-time double ergodic averages

Density theorems for anisotropic point configurations

The density of sets containing large similar copies of finite sets

Convergence of ergodic-martingale paraproducts

A Szemerédi-type theorem for subsets of the unit cube

Fourier restriction implies maximal and variational Fourier restriction

A variational restriction theorem

Boxes, extended boxes, and sets of positive upper density in the Euclidean space

Characterizations of democratic systems of translates on locally compact abelian groups

A sharp nonlinear Hausdorff-Young inequality for small potentials

On side lengths of corners in positive density subsets of the Euclidean space

Bellman functions and Lp estimates for paraproducts

Power-type cancellation for the simplex Hilbert transform

On the combined use of GW approximation and cumulant expansion in the calculations of quasiparticle spectra: The paradigm of Si valence bands

Norm-variation of ergodic averages with respect to two commuting transformations

On a trilinear singular integral form with determinantal kernel

Sharp $L^{p}$ estimates of powers of the complex Riesz transform

Bellman functions and $L^{p}$ estimates for paraproducts