Bolt and Tieman (2008) suggested that profit function non-concavities may account for the prevalence of skewed pricing by two-sided platform businesses. In the Rochet-Tirole (2003) model, however non-concavity is not necessary for highly skewed pricing. Ubiquitous high pass-through rates are sufficient but implausible. In the Armstrong (2006) model, non-concavity is neither necessary nor suffic...

In this article we discuss lattice convexity and concavity of Calderón-Lozanovskii space Eφ , generated by a quasi-Banach space E and an increasing Orlicz function φ. We give estimations of convexity and concavity indices of Eφ in terms of Matuszewska-Orlicz indices of φ as well as convexity and concavity indices of E. In the case when Eφ is a rearrangement invariant space we also provide some ...

This research evaluated whether adult morphological sex estimation methods of the innominate could be adapted and applied to subadults. The subpubic concavity, described by Phenice (1969) and revised by Klales et al. (2012), was modified for use with subadults. Two observers scored radiographic images from the PATRICIA database of 334 individuals of both sexes aged between 1.19 and 20.47 years....

Abstract. Shape constraints play an increasingly prominent role in nonparametric function estimation. While considerable recent attention has been focused on log concavity as a regularizing device in nonparametric density estimation, weaker forms of concavity constraints encompassing larger classes of densities have received less attention but offer some additional flexibility. Heavier tail beh...

Introduction Logarithmic concavity is a property of a sequence of real numbers, occurring throughout algebraic geometry, convex geometry, and combinatorics. A sequence of positive numbers a0,... ,ad is log-concave if a2 i ≥ ai−1ai+1 for all i. This means that the logarithms, log(ai), form a concave sequence. The condition implies unimodality of the sequence (ai), a property easier to visualize:...

For divisor methods of apportionment with concave up or concave down rounding functions, we prove explicit formulas for the threshold values—the lower and upper bounds for the percentage of population that are necessary and sufficient for a state to receive a particular number of seats. Among the rounding functions with fixed concavity are those based on power means, which include the methods o...

The traditional Canny edge detector has some drawbacks. Gaussian filter can’t remove the impulsive noise. Moreover, it is difficult to automatically select the dual-threshold. Especially when the noise intensity increases, the dual-threshold selection method of traditional Canny detector is invalid. In this paper, we present an adaptive Canny edge detector using histogram concavity analysis. Th...

A set is called semidefinite representable or semidefinite programming (SDP) representable if it can be represented as the projection of a higher dimensional set which is represented by some Linear Matrix Inequality (LMI). This paper discuss the semidefinite representability conditions for convex sets of the form SD(f) = {x ∈ D : f(x) ≥ 0}. Here D = {x ∈ R n : g1(x) ≥ 0, · · · , gm(x) ≥ 0} is a...