On properties and applications of (p,q)-extended τ-hypergeometric functions

We introduce the $(p,q)$-extended τ-hypergeometric and confluent hypergeometric functions along with their integral representations. We also present closed integral expressions for the Mathieu-type a-series and for the associated alternating versions whose terms contain the $(p,q)$-extended τ-hypergeometric functions with related contiguous functional relations.     

Existence and regularity of solutions for a class of singular (p(x), q(x))-Laplacian systems

In this paper, we study the existence of positive smooth solutions for a class of singular (p(x), q(x))-Laplacian systems using sub and supersolution methods.     

On the Cauchy Problem for D t 2-D xa(t,x)D x in the Gevrey Class of Order s > 2

We study the Cauchy problem for second order hyperbolic equations with non negative characteristic form of two independent variables. We show that for such equations in divergence-free form, the Cauchy problem is well posed in the Gevrey class of order less than 5/2.     

On Huppert’s Conjecture for 3 D 4(q), q ≥ 3

Let G be a finite group and cd(G) be the set of all complex irreducible character degrees of G. Bertram Huppert conjectured that if H is a finite nonabelian simple group such that cd(G) = cd(H), then G???H × A, where A is an abelian group. In this paper, we verify the conjecture for the family of simple exceptional groups of Lie type ³ D ₄(q), when q?≥?3.     

Multi-step hybrid methods for special second-order differential equations y″(t) = f(t,y(t))

In this paper, multi-step hybrid methods for solving special second-order differential equations y^″(t) = f(t,y(t)) are presented and studied. The new methods inherit the frameworks of RKN methods and linear multi-step methods and include two-step hybrid methods proposed by Coleman (IMA J. Numer. Anal. 23, 197–220, 8) as special cases. The order conditions of the methods were derived by using the SN-series defined on the set SNT of SN-trees. Based on the order conditions, we construct two explicit four-step hybrid methods, which are convergent of order six and seven, respectively. Numerical results show that our new methods are more efficient in comparison with the well-known high quality methods proposed in the scientific literature.     

On the structural properties of the weight space L p(x),ω for 0 < p(x) < 1

The main purpose of this paper is to study the weight space L _p(x),ω for 0 < p(x) < 1 as well as the topology of this space. Embeddings between different Lebesgue spaces with variable exponent of summability are established. In particular, it is proved that the set of all linear continuous functionals over L _p(x),ω for 0 < p(x) < 1 consists only of the zero functional.     

On the Cauchy problem for D t 2–D x a(t,x) n D x

Abstract The well posedness of the Cauchy problem for the operator P=D_t²–D_xa(t,x)ⁿD_x, with data on t=0 is studied assuming a ∈ C^N( (R)), s₀>1 and sufficiently close to 1, a(t,x)≥ 0. Well posedness is proved in Gevrey classes γ^(s), for , n≥ n₀. Keywords: Partial differential equations, Cauchy problem, Well posedness     

(U(p, q), U(p − 1, q)) is a generalized Gelfand pair

Denote by G = U(p, q) the orthogonal group of the sesqui-linear quadratic form on and let H ₁ = U(p − 1, q) be the stabilizer of the first unit vector e ₁. Let H ₀ = U(1) and set H = H ₀ × H ₁. Define the character χ _l of H by where . Define the anti-involution σ on G by . In this note we show that any distribution T on G satisfying T(h ₁ gh ₂) = χ _l (h ₁ h ₂) T(g) (g ∈ G; h ₁, h ₂ ∈ H) is invariant under the anti-involution σ. This result implies that (G,  H ₁) is a generalized Gelfand pair.      

Inequalities and equalities for ℓ = 2 (Sylvester), ℓ = 3 (Frobenius), and ℓ &gt; 3 matrices

This paper gives simple proofs of the Sylvester (? = 2) and Frobenius (? = 3) inequalities. Moreover, a new sufficient condition for the equality of the Frobenius inequality is provided. In addition, an extension for ? > 3 matrices and an application to generalized inverses are provided.     

General function spaces. III(SpacesB p,q g(x) andF p,q g(x) , 1<p<∞: basic properties)

qNАстОьЩАь РАБОтА (А тАк жЕ ЕЕ пРОДОлжЕНИЕ — РА БОтА «ОБЩИЕ ФУНкцИОНАльН ыЕ пРО-стРАНстВА, IV») пОсВьЩЕНА ИсслЕДОВ АНИУ БАНАхОВых пРОст РАНстВB _{p, q} ^g(x) ИF _p,q ^g(x) РАспРЕДЕлЕНИИ (ОБОБЩЕННых) ВR _n . В спЕц ИАльНых слУЧАьх ЁтИ пРОстРАНстВА РОДстВ ЕННы ИжВЕстНыМ клАсс АМ сОБОлЕВА—лЕБЕгА—БЕ сОВА, ИжОтРОпНыМ И АНИ жОтРОпНыМ. жДЕсь РАссМАтРИВАУт сь слЕДУУ-ЩИЕ сВОИстВА: плОтНОсть г лАДкИх ФУНкцИИ, ЁкВИВ АлЕНтНыЕ НОРМы, ИНтЕРпОльцИь, В клУЧЕНИь И сРАВНЕНИь. ОБЩИЕ ФУНкцИОНАльНы Е пРОстРАНстВА. III (пРОстРАНстВАB _p,q ^g(x) ИF _p,q ^g(x) , 1     

Automatic quadrature of functions of the formg(¦f(x¦)

The standard routine QAGE from Quadpack is modified to allow the efficient evaluation of integrals of the form _a ^b g(¦f(x)¦)dx, wheref andg are assumed to be smooth. Using function values available during the adaptive integration process, zeros off are found and used as subdivision points. The technique compares favourably with both the original bisection strategy and the nonuniform trisection strategy of Berntsen et al. The modified algorithm extends the class of integrals that can be integrated with an automatic code, since it copes with problem integrals that can not be integrated using the bisection or trisection strategies.     

On Proinov’s bound for the quadrature error of functions having a given modulus of continuity

Summary We discuss the question, under which conditions Proinovs upper bound for the quadrature error of functions having a given modulus of continuity is not improvable. Improvability usually holds if the quadrature formula is not a Riemannian sum. We derive a condition on the second Peano kernel yielding always the sharpness of Proinovs result. This condition is applicable to Gaussian quadrature.