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Feng Qi

Publications and source records attributed to Feng Qi.

At least 109 records · Page 6Linked to original sources
arXiv2013

Explicit formulas for computing Bernoulli numbers of the second kind and Stirling numbers of the first kind

In the paper, by establishing a new and explicit formula for computing the $n$-th derivative of the reciprocal of the logarithmic function, the author presents new and explicit formulas for calculating Bernoulli numbers of the second kind and Stirling numbers of the first kind. As consequences of these formulas, a recursion for Stirling numbers of the first kind and a new representation of the reciprocal of the factorial $n!$ are derived. Finally, the author finds several identities and integral representations relating to Stirling numbers of the first kind.

math.CO↗
arXiv2013

Some Bernstein functions and integral representations concerning harmonic and geometric means

It is general knowledge that the harmonic mean $H(x,y)=\frac2{\frac1x+\frac1y}$ and that the geometric mean $G(x,y)=\sqrt{xy}\,$, where $x$ and $y$ are two positive numbers. In the paper, the authors show by several approaches that the harmonic mean $H_{x,y}(t)=H(x+t,y+t)$ and the geometric mean $G_{x,y}(t)=G(x+t,y+t)$ are all Bernstein functions of $t\in(-\min\{x,y\},\infty)$ and establish integral representations of the means $H_{x,y}(t)$ and $G_{x,y}(t)$.

math.CA↗
arXiv2013

A new proof of the geometric-arithmetic mean inequality by Cauchy's integral formula

Let $a=(a_1,a_2,...c,a_n)$ for $n\in\mathbb{N}$ be a given sequence of positive numbers. In the paper, the authors establish, by using Cauchy's integral formula in the theory of complex functions, an integral representation of the principal branch of the geometric mean {equation*} G_n(a+z)=\Biggl[\prod_{k=1}^n(a_k+z)\Biggr]^{1/n} {equation*} for $z\in\mathbb{C}\setminus(-\infty,-\min\{a_k,1\le k\le n\}]$, and then provide a new proof of the well known GA mean inequality.

math.CA↗
arXiv2013

Some inequalities for complete elliptic integrals

In the paper, by using Lupaş integral inequality, the authors find some new inequalities for the complete elliptic integrals of the first and second kinds. These results improve some known inequalities.

math.CA↗
arXiv2013

Geometric convexity of the generalized sine and the generalized hyperbolic sine

In the paper, the authors prove that the generalized sine function $\sin_{p,q}(x)$ and the generalized hyperbolic sine function $\sinh_{p,q}(x)$ are geometrically concave and geometrically convex, respectively. Consequently, the authors verify a conjecture posed in the paper "B. A. Bhayo and M. Vuorinen, On generalized trigonometric functions with two parameters, J. Approx. Theory 164 (2012), no.~10, 1415\nobreakdash--1426; Available online at \url{http://dx.doi.org/10.1016/j.jat.2012.06.003}".

math.CA↗
arXiv2013

Complete monotonicity of a family of functions involving the tri- and tetra-gamma functions

The psi function $ψ(x)$ is defined by $ψ(x)=\frac{Γ'(x)}{Γ(x)}$ and $ψ^{(i)}(x)$ for $i\in\mathbb{N}$ denote polygamma functions, where $Γ(x)$ is the gamma function. In this paper, we prove that the function $$ [ψ'(x)]^2+ψ"(x)-\frac{x^2+λx+12}{12x^4(x+1)^2} $$ is completely monotonic on $(0,\infty)$ if and only if $λ\le0$, and so is its negative if and only if $λ\ge4$. From this, some inequalities are refined and sharpened.

math.CA↗
arXiv2012

Complete monotonicity, completely monotonic degree, integral representations, and an inequality related to the exponential, trigamma, and modified Bessel functions

In the paper, the authors verify the complete monotonicity of the difference $e^{1/t}-ψ'(t)$ on $(0,\infty)$, compute the completely monotonic degree and establish integral representations of the remainder of the Laurent series expansion of $e^{1/z}$, and derive an inequality which gives a lower bound for the first order modified Bessel function of the first kind.

math.CA↗
arXiv2012

An Improved WBF Algorithm for Higher-Speed Decoding of LDPC Codes

Due to the speed limitation of the conventional bit-chosen strategy in the existing weighted bit flipping algorithms, a high-speed LDPC decoder cannot be realized. To solve this problem, we propose a fast weighted bit flipping (FWBF) algorithm. Specifically, based on the stochastic error bitmap of the received vector, a partially parallel bit-choose strategy is adopted to lower the delay of choosing the bit flipped. Because of its partially parallel structure, the novel strategy can be well incorporated into the LDPC decoder [1]. The analysis of the decoding delay demonstrates that, the decoding speed can be greatly improved by adopting the proposed FWBF algorithm. Further, simulation results verify the validity of the proposed algorithm.

cs.IT↗
arXiv2012

On the $q$-Genocchi numbers and polynomials with weight zero and their applications

In this paper, the authors deal with the $q$-Genocchi numbers and polynomials with weight zero. They discover some interesting relations via the $p$-adic $q$-integral on $\mathbb{Z}_{p}$ and familiar basis Bernstein polynomials. Finally, the authors show that the $p$-adic $\log$ gamma functions are associated with the $q$-Genocchi numbers and polynomials with weight zero.

math.NT↗
arXiv2012

Some sharp inequalities involving Seiffert and other means and their concise proofs

In the paper, by establishing the monotonicity of some functions involving the sine and cosine functions, the authors provide concise proofs of some known inequalities and find some new sharp inequalities involving the Seiffert, contra-harmonic, centroidal, arithmetic, geometric, harmonic, and root-square means of two positive real numbers $a$ and $b$ with $a\ne b$.

math.CA↗
arXiv2012

A note on the modified q-Genocchi numbers and polynomials with weight (α,β) and their interpolation function at negative integers

The purpose of this paper concerns to establish modified q-Genocchi numbers and polynomials with weight (α,β). In this paper we investigate special generalized q-Genocchi polynomials and we apply the method of generating function, which are exploited to derive further classes of q-Genocchi polynomials and develop q-Genocchi numbers and polynomials. By using the Laplace-Mellin transformation integral, we define q-Zeta function with weight (α,β) and by presenting a link between q-Zeta function with weight (α,β) and q-Genocchi numbers with weight (α,β) we obtain an interpolation formula for the q-Genocchi numbers and polynomials with weight (α,β). Also we derive distribution formula (Multiplication Theorem) and Witt's type formula for modified q-Genocchi numbers and polynomials with weight (α,β) which yield a deeper insight into the effectiveness of this type of generalizations for q=Genocchi numbers and polynomials. Our new generating function possess a number of interesting properties which we state in this paper.

math.CO↗