Revistas académicas de la Universidad Católica del Norte
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A note on Büchi's problem for p-adic numbers
No full textWe prove that for any prime p and any integer k > 2,there exist in the ring Zp of p-adic integers arbitrarily long sequences whose sequence of k-th powers 1) has its k-th difference sequence equal to the constant sequence (k!); and 2) is not a sequence of consecutive k-th powers. This shows that the analogue of Buchi's problem for higher powers has a negative answer over Zp.This result for k = 2 was recently obtained by J. Browkin
A proposed reparametrization of gamma distribution for the analysis of data of rainfall-runoff driven pollution
No full textA generalized gamma (GG) distribution of four parameters was first introduced by Amoroso 1925, and since then, different distributions emerged as subclasses of this model. This model is commonly used to model lifetime data or data with a right skewed unimodal density function. In this article, we use a reparameterization of the GG distribution that is compared with other usual two-parameter distributions, Weibull, generalized exponential (Gupta and Kundu 1999), and gamma, using a real data set with a high coefficient of asymmetry and kurtosis (Valenzuela M. 2009). Akaike's information criterion and Bayesian information criterion indicates that our reparametrization of the gamma distribution is better. Besides a Monte Carlo simulation study, shows the behavior of five estimation methods: least squared, weighted least squared, moments, probability weighted moments and maximum likelihood methods
On topological conjugacy of left invariant flows on semisimple and affine lie groups
No full textIn this paper, we study the flows of nonzero left invariant vector fields on Lie groups with respect to topological conjugacy. Using the fundamental domain method, we are able to show that on a simply connected nilpotent Lie group any such flows are topologically conjugate. Combining this result with the Iwasawa decomposition, we find that on a noncompact semisimple Lie group the flows of two nilpotent or abelian fields are topologically conjugate. Finally, for affine groups G = HV, V ≅ n, we show that the conjugacy class of a left invariant vector field does not depend on its Euclidean component
The reconstruction of a periodic structure from its dynamical behaviour
No full textThis work is related to the inverse problem in vibration produced in a special type of mechanical structure known as periodic structure. This problem consist in determining the stiffness and mass parameter of the structure from the natural frequencies and vibrations modes. The problem concern with the inverse eigenvalue problem for a specially structured Jacobi matrix which contains the desired parameters. Necessary conditions to be applied to the data to obtain a real system are derived and a numerical procedure is develop. Some numerical examples are presente
A new definition of S* Closedness in L-Topological Spaces
No full textIn this paper, a new notion of S* closedness in L-topological Spaces is introduced by means of semi-open L-"sets and their inequality where L is a complete DeMorgan algebra.This new definition doesn't rely on the structure of basic lattice L. It can be characterized by means of semi-open L-"sets and their inequality . When L is completely distributive DeMorgan algebra, its many characterizations are presented
Investigating the use of stratified percentile ranked set sampling method for estimating the population mean
No full textStratified percentile ranked set sampling (SPRSS) method is suggested for estimating the population mean. The SPRSS is compared with the simple random sampling (SRS), stratified simple random sampling (SSRS) and stratified ranked set sampling (SRSS). It is shown that SPRSS estimator is an unbiased estimator of the population mean of symmetric distributions and is more efficient than its counterparts using SRS, SSRS and SRSS based on the same number of measured units
Schauder basis in a locally k-convex space and perfect sequence spaces
No full textIn this work, we are dealing with the natural topology in a perfect sequence space and the transfert of topologies of a locally K — convex space E with a Schauder basis (ei )i to such Space. We are also interested with the compatible topologies on E for which the basis(ei )i is equicontinuous, and the weak basis problem. Finally, we give some applications to barrelled Spaces and G—Spaces
Triple generating functions of jacobi polynomials of two variables
No full textThe present paper is a study of triple generating functions of Jacobi polynomials of two variables
Some Mathieu–type series for the I–function occuring in the Fokker–Planck equation
No full textClosed form expressions are obtained for a family of convergent Mathieu type a-series and its alternating variants, whose terms contain an I-function which is a generalization of the Fox's H-function. The results derived are of general character and provide an elegant generalization for the closed form expressions of these series associated with the H-function by Pogány, for Fox-Wright functions by Pogány and Srivastava and for pFq and Meijer's G-function by Pogány and Tomovski, and others
Inverse spread limit of a nonnegative matrix
No full textFor a given nonnegative n × n matrix A consider the following quantity as long as the denominator is positive. It is simply the ratio between the smallest and the largest entries of Am. We call s(Am) the inverse spread of Am which is interpreted as a measure of the maximum variation among the entries of Am in the multiplicative and reciprocal sense. Smaller s(Am) means a larger variation for Am. Clearly 0 = s(Am) = 1 for all m = 1, 2, . . . We study the asymptotic behavior of s(Am), that is, the behavior of s(Am) as m → ∞. The study arises from evolutionary biology