For little q-Jacobi polynomials and q-Hahn polynomials we give particular q-hypergeometric series representations in which the termwise q = 0 limit can be taken. When rewritten in matrix form, these series representations can be viewed as LU factorizations. We develop a general theory of LU factorizations related to complete systems of orthogonal polynomials with discrete orthogonality relation...

let r and s be reduced rings with identities whose idempotents are central, and let m be an(r, s)-bimodule such that annr (m)=0. in this paper, we determine first the structure of automorphisms ofthe triangular ring, =sr mt0, and then, for all automorphisms α ,β of t we determine the structureof (α,β)-derivations of t.

The problem of structural stability wave systems with great numbers degrees freedom directly concerns the issue redistribution energy fluxes in structured vortex beams that ensure their under propagating and focusing. A special place this variety is occupied by spiral capable mapping complex figures, letters even words. Spiral contain an infinite set Laguerre-Gauss a strong sequence topological...

The main purpose of this paper is to determine the fine spectrum of the generalized upper triangular double-band matrices uv over the sequence spaces c0 and c. These results are more general than the spectrum of upper triangular double-band matrices of Karakaya and Altun[V. Karakaya, M. Altun, Fine spectra of upper triangular doubleband matrices, Journal of Computational and Applied Mathematics...

background and aims. at present, cone beam computed tomography (cbct) has become a substitute for computed tomography (ct) in dental procedures. the metallic materials used in dentistry can produce artifacts due to the beam hardening phenomenon. these artifacts decrease the quality of images. in the present study, the number of artifacts as a result of beam hardening in the images of dental imp...

The problem we are dealing with is the following: find two sequences an and bn such that the average of the first bn triangular numbers (starting with the triangular number 1) is still a triangular number, precisely the an-th triangular number. We get also some side results: for instance one of the sequence instrumental to finding the asked for sequences turns out to be a bisection of the seque...

we survey some recent results on cocharacters of upper triangular matrices. in particular, we deal both with ordinary and graded cocharacter sequence; we list the principal combinatorial results; we show di erent tech-niques in order to solve similar problems.

The article proposes a method for measuring the refractive index using goniometric system that does not require prism angle, which simplifies measurement process compared to widely used methods of minimum deviation and autocollimation. This can be measure samples in form triangular prisms visible, ultraviolet infrared ranges. To implement method, was used. obtain reflection refracted beam, fixe...

Additively manufactured polymer parts are often designed like composite sandwich structures. In this work, beam-like specimens with hexagonal, triangular and rectangular infills were different infill densities. An influence of the shape on overall stiffness was observed. The bending hexagonal between 13% 25% lower than that other two cases instead showed similar performances. Numerical simulati...