Simple image set of linear mappings in a max-min algebra

For a given linear mapping, determined by a square matrix A in a max-min algebra, the set S_A consisting of all vectors with a unique pre-image (in short: the simple image set of A) is considered. It is shown that if the matrix A is generally trapezoidal, then the closure of S_A is a subset of the set of all eigenvectors of A. In the general case, there is a permutation π, such that the closure of S_A is a subset of the set of all eigenvectors permuted by π. The simple image set of the matrix square and the topological aspects of the problem are also described.     

On spherical expansions of zonal functions on Euclidean spheres

This paper describes a new approach to the problem of computing spherical expansions of zonal functions on Euclidean spheres. We derive an explicit formula for the coefficients of the expansion expressing them in terms of the Taylor coefficients of the profile function rather than (as done usually) in terms of its integrals against Gegenbauer polynomials. Our proof of this result is based on a polynomial identity equivalent to the canonical decomposition of homogeneous polynomials and uses only basic properties of this decomposition together with simple facts concerning zonal harmonic polynomials. As corollaries, we obtain direct and apparently new derivations of the so-called plane wave expansion and of the expansion of the Poisson kernel for the unit ball. Received: 26 January 2007     

The umbral calculus on logarithmic algebras

D. E. Loeb and G.-C. Rota, using the operator of differentiation D, constructed the logarithmic algebra that is the generalization of the algebra of formal Laurent series. They also introduced Appell graded logarithmic sequences and binomial (basic) graded logarithmic sequences as sequences of elements of the logarithmic algebra and extended the main results of the classical umbral calculus on such sequences. We construct an algebra by an operator d that is defined by the formula (1.1). This algebra is an analog of the logarithmic algebra. Then we define sequences analogous to Boas-Buck polynomial sequences and extend the main results of the nonclassical umbral calculus on such sequences. The basic logarithmic algebra constructed by the operator of q-differentiation is considered. The analog of the q-Stirling formula is obtained.     

Moments of products of elliptic integrals

We consider the moments of products of complete elliptic integrals of the first and second kinds. In particular, we derive new results using elementary means, aided by computer experimentation and a theorem of W. Zudilin. Diverse related evaluations, and two conjectures, are also given.     

Characteristic expansions and multiplicative addition theorems

The notions of -polynomial expansion % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaqefeKCPfgBaG% qbciaa-DgacaGGOaWexLMBb50ujbqeguuDJXwAKbacgiGae4hEaGNa% ey4kaSsefCuzVj3zPfgaiCGacaqF5bGaaiykaiabg2da9iaa-Dgaca% GGOaGae4hEaGNaaiykaiabgUcaRiaa-DgacaGGOaGaa0xEaiaacMca% cqGHRaWkdaaeqbqaaiaadchadaWgaaWcbaGaamOBaaqabaGccaGGOa% Gaeqy1dOMaaiikaiab+Hha4jaacMcacaGGPaWaaSaaaeaacaqF5bWa% aWbaaSqabeaacaqFUbaaaaGcbaGaamOBaiaacgcaaaGaey4kaSIaam% OCaiaacIcacqGF4baEcqGFSaalcaqF5bGaaiykaiaacYcaaSqaaiaa% d6gatuuDJXwAK1uy0HMmaeXbfv3ySLgzG0uy0HgiuD3BaGacciab8v% MifkaaigdaaeqaniabggHiLdaaaa!7116!\[g(x + y) = g(x) + g(y) + \sum\limits_{n \geqslant 1} {p_n (\varphi (x))\frac{{y^n }}{{n!}} + r(x,y),} \] and multiplicative addition theorems % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeyOeI0YaaS% aaaeaacaaIXaaabaGaamyAaaaadaWcaaqaaiabgkGi2cqaaiabgkGi% 2kaadshaaaqeduuDJXwAKbYu51MyVXgaiuaacqWFvpGAcaWG0bGaey% ypa0JaamisamaaBaaaleaacaGGOaaabeaakmaaBaaaleaacaGGPaaa% beaakiab-v9aQjaadshaaaa!4A8D!\[ - \frac{1}{i}\frac{\partial }{{\partial t}}\varphi t = H_( _) \varphi t\] are introduced and characterization of some -polynomial expansions and multiplicative addition theorems are obtained.Sponsored by the International Science Foundation (Soros) Grant M3Z00 and by Russian Foundation of Fundamental Research 94-01-0144.     

Die Laguerre-Pinney-Transformation

Ohne Zusammenfassung

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On solving certain differential equations with variable coefficients

We show how to solve certain types of linear ordinary differential equations with variable coefficients by using Appell polynomials.     

A method for solving differential equations of fractional order

In this paper, we consider Caputo type fractional differential equations of order 0<α<1$0<\alpha <1$ with initial condition x(0)=_x0$x\left(0\right)=x_0$. We introduce a technique to find the exact solutions of fractional differential equations by using the solutions of integer order differential equations. Generalization of the technique to finite systems is also given. Finally, we give some examples to illustrate the applications of our results.     

Integrals involving Gegenbauer and Hermite polynomials on the imaginary axis

Summary The integral _- [C _2n (it)]^–2(1+t ²)^–-1/2 dt is evaluated for > –1/2 whereC _2n is the Gegenbauer polynomial of degree 2n. Letting gives the value _- [H _2n (it)]^–2 e ^{1-1/2t 2} dt involving the Hermite polynomialH _2n of degree 2n. The result is obtained using Gegenbauer functions of the second kind.     

Asymptotic method for Dougall's bilateral hypergeometric sums

By means of the modified Abel lemma on summation by parts, a recurrence relation for Dougall's bilateral -series is established with an extra natural number parameter m. Then the steepest descent method allows us to compute the limit for m→∞, which leads us surprisingly to a completely new proof of the celebrated bilateral -series identity due to Dougall (1907). The same approach applies also to the bilateral very well-poised -series identity [J. Dougall, On Vandermonde's theorem and some more general expansions, Proc. Edinburgh Math. Soc. 25 (1907) 114-132].     

Legendre inversions and balanced hypergeometric series identities

By means of Legendre inverse series relations, we prove two terminating balanced hypergeometric series formulae. Their reversals and linear combinations yield several known and new hypergeometric series identities.     

Abel's method on summation by parts and terminating well-poised q-series identities

The Abel method on summation by parts is reformulated to present new and elementary proofs of several classical identities of terminating well-poised basic hypergeometric series, mainly discovered by [F H. Jackson, Certain q-identities, Quart. J. Math. Oxford Ser. 12 (1941) 167–172]. This strengthens further our conviction that as a traditional analytical instrument, the revised Abel method on summation by parts is indeed a very natural choice for working with basic hypergeometric series.