Studia Mathematica: Recent submissions
Now showing items 61-80 of 215
-
Gauss's definition of the gamma function
(2008)The present paper gives a historical account on extending the factorial function to complex numbers by Gauss. -
Sign-changing Lyapunov functions in linear extensions of dynamical systems
(2008)In this note we consider sets of linear extensions of dynamical systems on a torus. We examine regularity of the systems by means of a given sign-changing Lyapunov function. The main result of the paper is to give ... -
Lichawski-Matkowski-Miś theorem on locally defined operators for functions of several variables
(2008)Let $D$ be a regular closed set in the open subspace $G ⊂ ℝ^n$ and $C^m(D)$ be the space of functions $f|_D$ such that $f ∈ C^m(G)$. The representation formulas for locally defined operators mapping $C^m(D)$ into $C^0(D)$ ... -
Riemann integrability of a nowhere continuous multifunction
(2008)We present an example of the Riemann integrable multifunction which is discontinuous at each point with respect to the Hausdorff metric. The constructed multifunction is neither lower nor upper semicontinuous. -
Annales Academiae Paedagogicae Cracoviensis. 63. Studia Mathematica 7
(Wydawnictwo Naukowe Akademii Pedagogicznej, Kraków, 2008) -
On the superstability of the cosine and sine type functional equations
(2016)In this paper, we study the superstablity problem of the cosine and sine type functional equations: $f(xσ(y)a) + f(xya) = 2f(x)f(y)$ and $f(xσ(y)a) − f(xya) = 2f(x)f(y)$, where $f : S → C$ is a complex valued function; ... -
New method to solve certain differential equations
(2016)A new method to solve stationary one-dimensional Schroedinger equation is investigated. Solutions are described by means of representation of circles with multiple winding number. The results are demonstrated using the ... -
Properties of two variables Toeplitz type operators
(2016)The investigation of properties of generalized Toeplitz operators with respect to the pairs of doubly commuting contractions (the abstract analogue of classical two variable Toeplitz operators) is proceeded. We ... -
Construction of a common element for the set of solutions of fixed point problems and generalized equilibrium problems in Hilbert spaces
(2016)In this paper, we propose and analyse an iterative algorithm for the approximation of a common solution for a finite family of k-strict pseudocontractions and two finite families of generalized equilibrium problems in the ... -
A sharp companion of Ostrowski’s inequality for the Riemann–Stieltjes integral and applications
(2016)A sharp companion of Ostrowski’s inequality for the Riemann-Stieltjes integral $∫_a^b f(t) du(t)$, where $f$ is assumed to be of $r-H-Hölder$ type on $[a, b]$ and $u$ is of bounded variation on $[a, b]$, is proved. ... -
Several observations about Maneeals - a peculiar system of lines
(2016)For an arbitrary triangle $ABC$ and an integer $n$ we define points $D_n$, $E_n$, $F_n$ on the sides $BC$, $CA$, $AB$ respectively, in such a manner that \[\frac{|AC|^n}{{|AB|}^n} = \frac{|CD_n|}{|BD_n|}, \frac{|AB|^ ... -
Affine analogues of the Sasaki-Shchepetilov connection
(2016)For two-dimensional manifold $M$ with locally symmetric connection $∇$ and with $∇-parallel$ volume element vol one can construct a flat connection on the vector bundle $TM ⊕ E$, where $E$ is a trivial bundle. The ... -
An integro-differential inequality related to the smallest positive eigenvalue of p(x)-Laplacian Dirichlet problem
(2016)We consider the eigenvalue problem for the p(x)-Laplace-Beltrami operator on the unit sphere. We prove same integro-differential inequalities related to the smallest positive eigenvalue of this problem. -
Strong ideals and horizontal ideals in pseudo-BCH-algebras
(2016)In this paper we define strong ideals and horizontal ideals in pseudo-BCH-algebras and investigate the properties and characterizations of them -
On the superstability of generalized d’Alembert harmonic functions
(2016)The aim of this paper is to study the superstability problem of the d’Alembert type functional equation \[f(x + y + z) + f(x + y + σ(z)) + f(x + σ(y) + z) + f(σ(x) + y + z)\] \[= 4f(x)f(y)f(z)\] for all $x, y, z ∈ G$, ... -
Annales Universitatis Paedagogicae Cracoviensis. 182. Studia Mathematica 15
(Wydawnictwo Naukowe Uniwersytetu Pedagogicznego, Kraków, 2016) -
À la recherche de la preuve perdue: a simple proof of the Ficken theorem
(2014)A new proof of the Ficken criterion is given together with a comment concerning the known proofs and related results. -
First-order systems of linear partial differential equations: normal forms, canonical systems, transform methods
(2014)In this paper we consider first-order systems with constant coefficients for two real-valued functions of two real variables. This is both a problem in itself, as well as an alternative view of the classical linear ... -
Semiprime rings with nilpotent Lie ring of inner derivations
(2014)We give an elementary and self-contained proof of the theorem which says that for a semiprime ring commutativity, Lie-nilpotency, and nilpotency of the Lie ring of inner derivations are equivalent conditions.