The paper presents a simple method to check a positiveness of symmetric multivariate polynomials on the unit multi-circle. The method is based on the sampling polynomials using the fast Fourier transform. The algorithm is described and its possible applications are proposed. One of the aims of the paper is to show that presented algorithm is significantly faster than commonly used method based on the semi-definite programming expression.
The absolute gravity measurements are an important tool for reliable monitoring geodynamic phenomena. Based on the experience with the absolute gravimeter FG5#215 (gravimeter of the Center for Earth Dynamics Research), the accuracy of FG5 absolute gravimeters is presented in this study. The instrumental reproducibility of this meter is characterized by the value of 0.7 μGal. Discussed are important environmental effects on gravity measurements, such as atmospheric and hydrological effects, understanding of which is necessary for correct and reliable interpretation of the repeated absolute gravity measurements in geodynamics., Vojtech Pálinkáš, Jakub Kostelecký and Jaroslav Šimek., and Obsahuje bibliografii
The perturbed Laplacian matrix of a graph G is defined as DL = D−A, where D is any diagonal matrix and A is a weighted adjacency matrix of G. We develop a Fiedler-like theory for this matrix, leading to results that are of the same type as those obtained with the algebraic connectivity of a graph. We show a monotonicity theorem for the harmonic eigenfunction corresponding to the second smallest eigenvalue of the perturbed Laplacian matrix over the points of articulation of a graph. Furthermore, we use the notion of Perron component for the perturbed Laplacian matrix of a graph and show how its second smallest eigenvalue can be characterized using this definition., Israel Rocha, Vilmar Trevisan., and Obsahuje seznam literatury
Matrix polynomials play an important role in the theory of matrix differential equations. We develop a fixed point method to compute solutions of matrix polynomials equations, where the matricial elements of the matrix polynomial are considered separately as complex polynomials. Numerical examples illustrate the method presented.
For a $C^1$-function $f$ on the unit ball $\mathbb B \subset \mathbb C ^n$ we define the Bloch norm by $\|f\|_\mathfrak B=\sup \|\tilde df\|,$ where $\tilde df$ is the invariant derivative of $f,$ and then show that $$ \|f\|_\mathfrak B= \sup _{z,w\in {\mathbb B} \atop z\neq w} (1-|z|^2)^{1/2}(1-|w|^2)^{1/2}\frac {|f(z)-f(w)|}{|w-P_wz-s_wQ_wz|}.$$.
† Pyrenicocephalus jarzembowskii, gen. et sp. n. (Hemiptera: Heteroptera: Enicocephalomorpha: Enicocephalidae: Enicocephalinae) from Early Eocene, London Clay, England, Isle of Sheppey, is described and illustrated according to the unique pyritized adult head reported as a larval enicocephalid head by Jarzembowski (1986). The head anatomy of similar and related genera of Enicocephalinae is compared and the close relationship of the new genus to a clade including the extant genera Oncylocotis, Embolorrhinus and Hoplitocoris is suggested, most probably as the sister genus to Hoplitocoris (presently with Afrotropical, East Palaearctic and Oriental range).
We study a generalization of the classical Henstock-Kurzweil integral, known as the strong $\rho $-integral, introduced by Jarník and Kurzweil. Let $(\mathcal S_{\rho } (E), \Vert \cdot \Vert )$ be the space of all strongly $\rho $-integrable functions on a multidimensional compact interval $E$, equipped with the Alexiewicz norm $\Vert \cdot \Vert $. We show that each element in the dual space of $(\mathcal S_{\rho } (E), \Vert \cdot \Vert )$ can be represented as a strong $\rho $-integral. Consequently, we prove that $fg$ is strongly $\rho $-integrable on $E$ for each strongly $\rho $-integrable function $f$ if and only if $g$ is almost everywhere equal to a function of bounded variation (in the sense of Hardy-Krause) on $E$.
An infinite series which arises in certain applications of the Lagrange-Bürmann formula to exponential functions is investigated. Several very exact estimates for the Laplace transform and higher moments of this function are developed.