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About 6,314 papers for “Concave function”

Concave function

Saul I. Gass, Carl M. Harris · 2001

Cited by 0

Strictly Quasi-Concave Function

Saul I. Gass, Michael C. Fu · 2013

Cited by 0

Concave loan demand function.

Zheng Zhang (88857), Joel Clovis (18404788), Peter Moffatt (18404791) et al. · Figshare · 2024

<div>This paper investigates the relationship between monetary policy and bank risk-taking by introducing a model wherein banks expend a level of costly monitoring effort to select low-risk projects, thereby reducing the risk associated with the loans they grant. The impact of monetary policy on bank risk-taking is examined through both theoretical models and empirical analysis. The paper compares theoretical models with different assumptions, revealing an unambiguous negative effect without the assumption of limited liability for banks, and an ambiguous effect with the assumption of limited liability for banks, influenced by the equity ratio. The empirical model employs unique quarterly data comprising balance sheet information for top-listed banks in the U.S. banking system from 2000 to 2017. The findings indicate that low-interest rates contribute to an increase in bank risk-taking. Moreover, this effect is more pronounced after the financial crisis and weaker before the crisis. Additionally, the impact is evident for undercapitalized banks and more substantial for those financed with a higher proportion of equity.</div>

Cited by 0Open access

The Piecewise Concave Function

Willard I. Zangwill · Management Science · 1967

An important function which is neither concave nor convex often arises in production and inventory models. This function is herein called piecewise concave and can be considered to be a generalization of the concave function. Essentially it is the maximum of a collection of concave functions. Various properties of piecewise concave functions are explored in this paper. In particular, a theory is developed to locate the point at which such functions are minimized. A short discussion of applications is included.

Cited by 33

Bounds for an operator concave function

Sever S Dragomir, Jun Ichi Fujii, Yūki Seo · Electronic Journal of Linear Algebra · 2013

Let and be unital positive linear maps satisfying some conditions with respect to positive scalars and . It is shown that if a real valued function f is operator concave on an interval J, then

Cited by 3Open access

Note on a Matrix-Concave Function

Heinz Neudecker, Shuangzhe Liu · Journal of Mathematical Analysis and Applications · 1995

Cited by 4

Santalo region of a log-concave function

Tal Weissblat · arXiv (Cornell University) · 2011

In this paper we define the Santalo region and the Floating body of a log-concave function. We then study their properties. Our main result is that any relation of Floating body and Santalo region of a convex body is translated to a relation of Floating body and Santalo region of an even log-concave function

Cited by 0Open access

Modularity of the concave composition generating function

George Andrews, Robert C. Rhoades, Sander Zwegers · Algebra & Number Theory · 2013

A composition of an integer constrained to have decreasing then increasing parts is called concave. We prove that the generating function for the number of concave compositions, denoted [math] , is a mixed mock modular form in a more general sense than is typically used.\n¶ We relate [math] to generating functions studied in connection with “Moonshine of the Mathieu group” and the smallest parts of a partition. We demonstrate this connection in four different ways. We use the elliptic and modular properties of Appell sums as well as [math] -series manipulations and holomorphic projection.\n¶ As an application of the modularity results, we give an asymptotic expansion for the number of concave compositions of [math] . For comparison, we give an asymptotic expansion for the number of concave compositions of [math] with strictly decreasing and increasing parts, the generating function of which is related to a false theta function rather than a mock theta function.

Cited by 30Open access

Concave function inequalities for sum of matrices

Feng Zhang · Electronic Journal of Linear Algebra · 2024

In this paper, we present some norm inequalities for concave functions, which generalize the main results in [Y. Zhang. Linear Algebra Appl., 574:60-66, 2019].

Cited by 0Open access

The duality implications of a concave aggregator function

Walter Diewert · Economics Letters · 1983

Cited by 1

Sequence Inequalities for the Logarithmic Convex (Concave) Function

Jian-She Sun · Victoria University Research Repository (Victoria University) · 2004

Let f be a positive strictly increasing logarithmic convex (or logarithmic concave) function on (0;1], then, for k being a nonnegative integer and n a natural number, the sequence 1 P n+k i=k+1 lnf( i

Cited by 2

Minimax concave bridge penalty function for variable selection

CHUA LAI CHOON · National University of Singapore · 2012

Ph.D

Cited by 1

The Minimal Perimeter of a Log-Concave Function

Niufa Fang, Zengle Zhang · Mathematics · 2020

Inspired by the equivalence between isoperimetric inequality and Sobolev inequality, we provide a new connection between geometry and analysis. We define the minimal perimeter of a log-concave function and establish a characteristic theorem of this extremal problem for log-concave functions analogous to convex bodies.

Cited by 0Open access

Cournot equilibrium in case of (-1)-concave price function

Detelina Kamburova, Rumen Marinov · Mathematica · 2019

We consider a class of homogeneous Cournot oligopolies with (-1)concave price function. We show some useful properties of the revenue function in case of (-1)-concave price function and prove the existence of an equilibrium in the continuous and non-differentiable case. A simple proof of an equilibrium uniqueness result in the smooth case with (-1)/N -concave (N-number of the firms in the market) price function is provided.

Cited by 2Open access

A study on concave optimization via canonical dual function

Jinghao Zhu, Shiming Tao, David Yang Gao · Journal of Computational and Applied Mathematics · 2008

Cited by 9

Minimizing a monotone concave function with laminar covering constraints

Mariko Sakashita, Kazuhisa Makino, Satoru Fujishige · Discrete Applied Mathematics · 2007

Cited by 10

One-Bit Compressive Sensing via Schur-Concave Function Minimization

Peng Xiao, Bin Liao, Jian Li · IEEE Transactions on Signal Processing · 2019

Much effort has been devoted to recovering sparse signals from one-bit measurements in recent years. However, it is still quite challenging to recover signals with high fidelity, which is desired in practical one-bit compressive sensing (1-bit CS) applications. We introduce the notion of Schur-concavity in this paper and propose to construct signals by taking advantage of Schur-Concave functions, which are capable of enhancing sparsity. Specifically, the Schur-concave functions can be employed to measure the degree of concentration, and the sparse solutions are obtained at the minima. As a representative of the Schur-concave family, the normalized ℓ 1 Shannon entropy function (ℓ 1 -SEF) is exploited. The resulting optimization problem is nonconvex. Hence, we convert it into a series of weighted ℓ 1 -norm subproblems, which are solved iteratively by a generalized fixed-point continuation algorithm. Numerical results are provided to illustrate the effectiveness and superiority of the proposed 1-bit CS algorithm.

Cited by 36

Hepatocyte spheroids in honeycomb concave microwells exhibit greater liver-specific function than those in circular concave microwells.

GeonHui Lee (2938278), JaeSeo Lee (2938281), HyunJik Oh (2938275) et al. · Figshare · 2016

(a) Analysis of metabolic functions of spheroids in the two types of microwells, as measured by the secretion of albumin. (b) Immunostaining of hepatocyte spheroids for albumin (primary hepatocytes; green in first row), DAPI (nuclei; blue), cytochrome P450 activity (CYP450; green in second row) and microfilaments (F-actin; red). (c) Quantified analysis of hepatocytes function test. Scale bars: 300 μm.

Cited by 0Open access

Computing maximum likelihood estimators of a log-concave density function

Kaspar Rufibach · Journal of Statistical Computation and Simulation · 2007

Abstract We consider the problem of estimating a density function that is assumed to be log-concave. This semi-parametric model includes many well-known parametric classes; such as Normal, Gamma, Laplace, Logistic, Beta or Extreme value distributions, for specific parameter ranges. It is known that the maximum likelihood estimator for the log-density is always a piecewise linear function with at most as many knots as observations, but typically much less. We show that this property can be exploited to design a linearly constrained optimization problem whose iteratively calculated solution yields the estimator. We compare several standard and one recently proposed algorithm regarding their performance on this problem. Keywords: Non-parametric density estimationShape restrictionInterior point MethodIterative convex minorant algorithmNewton method on subspace Additional informationNotes on contributorsKaspar Rufibach Email: kaspar.rufibach@stat.unibe.ch

Cited by 44