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Publications Influence

An extension of Vietoris's inequalities

- S. Koumandos
- Mathematics
- 22 February 2007

We establish a best possible extension of a famous Theorem of Vietoris about the positivity of a general class of cosine sums. Our result refines and sharpens several earlier generalizations of this… Expand

33 7

Remarks on some completely monotonic functions

- S. Koumandos
- Mathematics
- 15 December 2006

Applying the Euler–Maclaurin summation formula, we obtain upper and lower polynomial bounds for the function xex−1, x>0, with coefficients the Bernoulli numbers Bk. This enables us to give simpler… Expand

44 4

On a conjecture for trigonometric sums and starlike functions

- S. Koumandos, S. Ruscheweyh
- Computer Science, Mathematics
- J. Approx. Theory
- 1 November 2007

TLDR

27 3- PDF

Inequalities for Trigonometric Sums

- S. Koumandos
- Mathematics
- 2012

We give a survey of recent results on positive trigonometric sums. Far-reaching extensions and generalizations of classical results are presented. We provide new proofs as well as additional remarks… Expand

19 3

On a monotonic trigonometric sum

- G. Brown, S. Koumandos
- Mathematics
- 1 June 1997

By establishing a cosine analogue of a result of Askey and Steinig on a monotonic sine sum, this paper sharpens and unifies several results associated with Young's inequality for the partial sums of… Expand

13 3

Completely monotonic functions of positive order and asymptotic expansions of the logarithm of Barnes double gamma function and Euler's gamma function

- S. Koumandos, H. Pedersen
- Mathematics
- 18 November 2008

Abstract We introduce completely monotonic functions of order r > 0 and show that the remainders in asymptotic expansions of the logarithm of Barnes double gamma function and Euler's gamma function… Expand

70 2- PDF

On a conjecture of Clark and Ismail

- H. Alzer, C. Berg, S. Koumandos
- Computer Science, Mathematics
- J. Approx. Theory
- 1 May 2005

Let Φm(x) = -xm ψ(m) (x),where ψ denotes the logarithmic derivative of Euler's gamma function. Clark and Ismail prove in a recently published article that if m ∈ {1, 2 ..... 16}, then Φm(m) is… Expand

11 2

The zeros of certain Lommel functions

- S. Koumandos, M. Lamprecht
- Mathematics
- 1 September 2012

Lommel’s function sμ,ν(z) is a particular solution of the differential equation z2y′′ + zy′ + (z2 − ν2)y = zμ+1. Here we present estimates and monotonicity properties of the positive zeros of… Expand

21 2- PDF

On the Positivity of Some Basic Legendre Polynomial Sums

- G. Brown, S. Koumandos, K. Wang
- Mathematics
- 1 June 1999

The positivity of the partial sums of the series of Legendre polynomials is a classical result of Fejer. The paper presents corresponding results for both even and odd Legendre polynomials with best… Expand

10 1

Series representations for γ and other mathematical constants

- H. Alzer, S. Koumandos
- Mathematics
- 20 February 2008

AbstractWe present series representations for some mathematical constants, like γ, π, log 2, ζ(3). In particular, we prove that the following representation for Euler’s constant is valid: $$
\gamma =… Expand

13 1