DSpace Collection: Volume 27 Number 3
http://hdl.handle.net/10525/459
Serdica Mathematical Journal Volume 27, Number 3, 2001The Collection's search engineSearch the Channelsearch
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A Survey of Counterexamples to Hilbert's Fourteenth Problem
http://hdl.handle.net/10525/480
Title: A Survey of Counterexamples to Hilbert's Fourteenth Problem<br/><br/>Authors: Freudenburg, Gene<br/><br/>Abstract: We survey counterexamples to Hilbert’s Fourteenth Problem,beginning with those of Nagata in the late 1950s, and including recent counterexamples in low dimension constructed with locally nilpotent derivations.Historical framework and pertinent references are provided. We also include8 important open questions.Mon, 01 Jan 2001 00:00:00 GMTContinuity of Pseudo-differential Operators on Bessel And Besov Spaces
http://hdl.handle.net/10525/479
Title: Continuity of Pseudo-differential Operators on Bessel And Besov Spaces<br/><br/>Authors: Moussai, Madani<br/><br/>Abstract: We study the continuity of pseudo-differential operators onBessel potential spaces Hs|p (Rn ), and on the corresponding Besov spacesB^(s,q)p (R ^n). The modulus of continuity ω we use is assumed to satisfy j≥0, ∑ [ω(2−j )Ω(2j )]2 < ∞ where Ω is a suitable positive function.Mon, 01 Jan 2001 00:00:00 GMTWeak Polynomial Identities for M1,1(E)
http://hdl.handle.net/10525/478
Title: Weak Polynomial Identities for M1,1(E)<br/><br/>Authors: Di Vincenzo, Onofrio; La Scala, Roberto<br/><br/>Abstract: We compute the cocharacter sequence and generators of theideal of the weak polynomial identities of the superalgebra M1,1 (E).<br/><br/>Description: * Partially supported by Universita` di Bari: progetto “Strutture algebriche, geometriche e descrizione degli invarianti ad esse associate”.Mon, 01 Jan 2001 00:00:00 GMTOn a Class of Generalized Elliptic-type Integrals
http://hdl.handle.net/10525/477
Title: On a Class of Generalized Elliptic-type Integrals<br/><br/>Authors: Garg, Mridula; Katta, Vimal; Kalla, S.<br/><br/>Abstract: The aim of this paper is to study a generalized form of elliptic-type integrals which unify and extend various families of elliptic-type integrals studied recently by several authors. In a recent communication [1] wehave obtained recurrence relations and asymptotic formula for this generalizedelliptic-type integral. Here we shall obtain some more results whichare single and multiple integral formulae, differentiation formula, fractionalintegral and approximations for this class of generalized elliptic-type integrals.Mon, 01 Jan 2001 00:00:00 GMTFirst Order Characterizations of Pseudoconvex Functions
http://hdl.handle.net/10525/476
Title: First Order Characterizations of Pseudoconvex Functions<br/><br/>Authors: Ivanov, Vsevolod<br/><br/>Abstract: First order characterizations of pseudoconvex functions areinvestigated in terms of generalized directional derivatives. A connectionwith the invexity is analysed. Well-known first order characterizations ofthe solution sets of pseudolinear programs are generalized to the case ofpseudoconvex programs. The concepts of pseudoconvexity and invexity donot depend on a single definition of the generalized directional derivative.Mon, 01 Jan 2001 00:00:00 GMTAnalog of Favard's Theorem for Polynomials Connected with Difference Equation of 4-th Order
http://hdl.handle.net/10525/475
Title: Analog of Favard's Theorem for Polynomials Connected with Difference Equation of 4-th Order<br/><br/>Authors: Zagorodniuk, S.<br/><br/>Abstract: Orthonormal polynomials on the real line {pn (λ)} n=0 ... ∞ satisfythe recurrent relation of the form: λn−1 pn−1 (λ) + αn pn (λ) + λn pn+1 (λ) =λpn (λ), n = 0, 1, 2, . . . , where λn > 0, αn ∈ R, n = 0, 1, . . . ; λ−1 = p−1 =0, λ ∈ C. In this paper we study systems of polynomials {pn (λ)} n=0 ... ∞ which satisfy the equation: αn−2 pn−2 (λ) + βn−1 pn−1 (λ) + γn pn (λ) + βn pn+1 (λ) +αn pn+2 (λ) = λ2 pn (λ), n = 0, 1, 2, . . . , where αn > 0, βn ∈ C, γn ∈ R,n = 0, 1, 2, . . ., α−1 = α−2 = β−1 = 0, p−1 = p−2 = 0, p0 (λ) = 1,p1 (λ) = cλ + b, c > 0, b ∈ C, λ ∈ C.It is shown that they are orthonormal on the real and the imaginary axesin the complex plane ...Mon, 01 Jan 2001 00:00:00 GMT