DSpace Collection: Volume 31 Number 3
http://hdl.handle.net/10525/1762
Serdica Mathematical Journal Volume 31, Number 3, 2005The Collection's search engineSearch the Channelsearch
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Robust Parametric Estimation of Branching Processes with a Random Number of Ancestors
http://hdl.handle.net/10525/1768
Title: Robust Parametric Estimation of Branching Processes with a Random Number of Ancestors<br/><br/>Authors: Stoimenova, Vessela<br/><br/>Abstract: The paper deals with a robust parametric estimation in branching processes {Zt(n)} having a random number of ancestors Z0(n) as bothn and t tend to infinity (and thus Z0(n) in some sense). The offspring distribution is considered to belong to a discrete analogue of the exponential family – the class of the power series offspring distributions. Robust estimators, based on one and several sample paths, are proposed and studied for all values of the offspring mean m, 0 < m < ∞, in the subcritical, critical and supercritical case.<br/><br/>Description: 2000 Mathematics Subject Classification: 60J80.Sat, 01 Jan 2005 00:00:00 GMTA Geometrical Construction for the Polynomial Invariants of some Reflection Groups
http://hdl.handle.net/10525/1767
Title: A Geometrical Construction for the Polynomial Invariants of some Reflection Groups<br/><br/>Authors: Sarti, Alessandra<br/><br/>Abstract: We construct invariant polynomials for the reflection groups[3, 4, 3] and [3, 3, 5] by using some special sets of lines on the quadric P1 × P1in P3. Then we give a simple proof of the well known fact that the ring ofinvariants are rationally generated in degree 2,6,8,12 and 2,12,20,30.<br/><br/>Description: 2000 Mathematics Subject Classification: Primary 20F55, 13F20; Secondary 14L30.Sat, 01 Jan 2005 00:00:00 GMTQuaternion Extensions of Order 16
http://hdl.handle.net/10525/1766
Title: Quaternion Extensions of Order 16<br/><br/>Authors: Michailov, Ivo<br/><br/>Abstract: We describe several types of Galois extensions having as Galois group the quaternion group Q16 of order 16.<br/><br/>Description: 2000 Mathematics Subject Classification: 12F12Sat, 01 Jan 2005 00:00:00 GMTOn Root Arrangements of Polynomial-Like Functions and their Derivatives
http://hdl.handle.net/10525/1765
Title: On Root Arrangements of Polynomial-Like Functions and their Derivatives<br/><br/>Authors: Kostov, Vladimir<br/><br/>Abstract: We show that for n = 4 they are realizable eitherby hyperbolic polynomials of degree 4 or by non-hyperbolic polynomials ofdegree 6 whose fourth derivatives never vanish (these are a particular caseof the so-called hyperbolic polynomial-like functions of degree 4).<br/><br/>Description: 2000 Mathematics Subject Classification: 12D10.Sat, 01 Jan 2005 00:00:00 GMTRecursive Methods for Construction of Balanced N-ary Block Designs
http://hdl.handle.net/10525/1764
Title: Recursive Methods for Construction of Balanced N-ary Block Designs<br/><br/>Authors: Gheribi-Aoulmi, Z.; Bousseboua, M.<br/><br/>Abstract: This paper presents a recursive method for the construction ofbalanced n-ary block designs.This method is based on the analogy between a balanced incompletebinary block design (B.I .E .B) and the set of all distinct linear sub-varieties ofthe same dimension extracted from a finite projective geometry. If V1is thefirst B.I .E .B resulting from this projective geometry, then by regarding anyblock of V1 as a projective geometry, we obtain another system of B.I .E .B.Then, by reproducing this operation a finite number of times, we get afamily of blocks made up of all obtained B.I .E .B blocks. The family beingpartially ordered, we can obtain an n-ary design in which the blocks areconsisted by the juxtaposition of all binary blocks completely nested. Thesen-ary designs are balanced and have well defined parameters. Moreover, aparticular balanced n-ary class is deduced with an appreciable reduction ofthe number of blocks.<br/><br/>Description: 2000 Mathematics Subject Classification: Primary 05B05; secondary 62K10.Sat, 01 Jan 2005 00:00:00 GMTProjectively Normal Line Bundles on K-Gonal Curves and Rational Surfaces
http://hdl.handle.net/10525/1763
Title: Projectively Normal Line Bundles on K-Gonal Curves and Rational Surfaces<br/><br/>Authors: Ballico, E.; Keem, C.<br/><br/>Abstract: Here we prove the projective normality of several special linebundles on a general k-gonal curve.<br/><br/>Description: 2000 Mathematics Subject Classification: 14H50.Sat, 01 Jan 2005 00:00:00 GMT