Discrete Kontorovich–Lebedev transforms

The Ramanujan Journal - Discrete analogs of the classical Kontorovich–Lebedev transforms are introduced and investigated. It involves series with the modified Bessel function or Macdonald...     

A Convolution Operator Related to the Generalized Mehler–Fock and Kontorovich–Lebedev Transforms

In this paper we study a generalization of an index integral involving the product of modified Bessel functions and associated Legendre functions. It is applied to a convolution construction associated with this integral, which is related to the classical Kontorovich–Lebedev and generalized Mehler–Fock transforms. Mapping properties and norm estimates in weighted L _p -spaces, 1 ≤ p ≤ 2, are investigated. An application to a class of convolution integral equations is considered. Necessary and sufficient conditions are found for the solvability of these equations in L ₂.     

On the polyconvolution for the Fourier cosine,Fourier sine,and Kontorovich–Lebedev integral transforms

The polyconvolution *₁ ( f,g,h )(x) \mathop {*}\limits_1 \left( {f,g,h} \right)(x) of three functions f, g, and h is constructed for the Fourier cosine (F _c ), Fourier sine (F _s ), and Kontorovich–Lebedev (K _iy ) integral transforms whose factorization equality has the form

New index transforms of the Lebedev–Skalskaya type

New index transforms, involving the real part of the modified Bessel function of the first kind as the kernel are considered. Mapping properties such as the boundedness and invertibility are investigated for these operators in the Lebesgue spaces. Inversion theorems are proved. As an interesting application, a solution of the initial value problem for the second-order partial differential equation, involving the Laplacian, is obtained. It is noted that the corresponding operators with the imaginary part of the modified Bessel function of the first kind lead to the familiar Kontorovich–Lebedev transform and its inverse.     

On the Fourier-Sine and Kontorovich–Lebedev Generalized Convolution Transforms and Their Applications

Ukrainian Mathematical Journal - We study generalized convolutions for the Fourier sine and Kontorovich–Lebedev transforms $$ left(hunderset{F_s,K}{ast }fright)(x) $$ in a two-parameter...     

The convolution for zero-order Mehler–Fock transform and pseudo-differential operator

The main aim of this paper is to find out the estimates of convolution for zero-order Mehler–Fock transform with various approaches. Pseudo-differential operator in terms of zero-order Mehler–Fock transform is defined and obtained its another integral representation. Further, its estimate in Lebesgue space has been studied. At the end some applications of zero-order Mehler–Fock transform and of convolution are discussed.     

Equidistribution for meromorphic transforms and the dd~c-method

In this paper we give an introduction to the notion of meromorphic transform. We describe some equidistribution problems and their solution, using the ddc-method. In particular, we give some statistical properties of the equilibrium measure for meromorphic maps on compact Kahler manifolds: K-mixing, exponential decay of correlations and central limit theorem.     

Characterization of Weyl operator in terms of Mehler–Fock transform

In this paper, we define the windowed-Mehler–Fock transform and introduce the corresponding Weyl transform. Further, we examine the boundedness of windowed-Mehler–Fock transform in Lebesgue space and establish some of its fundamental properties. Also, we give the criteria of boundedness and compactness of Weyl transform in Lebesgue space.     

Symmetry and Classification of the Dirac–Fock Equation

We consider the properties of the Dirac–Fock equation with differential operators of the first-order symmetry. For a relativistic particle in an electromagnetic field, we describe the covariant properties of the Dirac equation in an arbitrary Riemannian space V₄ with the signature (?1,?1,?1, 1). We present a general form of the differential operator with a first-order symmetry and characterize the pair of such commuting operators. We list the spaces where the free Dirac equation admits at least one differential operator with a first-order symmetry. We perform a symmetry classification of electromagnetic field tensors and construct complete sets of symmetry operators.     

New upper bounds for the Davenport and for the Erdős–Ginzburg–Ziv constants

Let G be a finite abelian group (written additively) of rank r with invariants n ₁, n ₂, . . . , n _r , where n _r is the exponent of G. In this paper, we prove an upper bound for the Davenport constant D(G) of G as follows; D(G) ≤ n _r + n _r-1 + (c(3) − 1)n _r-2 + (c(4) − 1) n _r-3 + · · · + (c(r) − 1)n ₁ + 1, where c(i) is the Alon–Dubiner constant, which depends only on the rank of the group \mathbb Z_nrⁱ{{\mathbb Z}_{n_r}^i}. Also, we shall give an application of Davenport’s constant to smooth numbers related to the Quadratic sieve.     

Hartree–Fock Theory for Pseudorelativistic Atoms

We study the Hartree–Fock model for pseudorelativistic atoms, that is, atoms where the kinetic energy of the electrons is given by the pseudo-relativistic operator . We prove the existence of a Hartree–Fock minimizer, and prove regularity away from the nucleus and pointwise exponential decay of the corresponding orbitals. Submitted: August 1, 2007. Accepted: November 8, 2007.