A triangle {a(n, k)}0≤k≤n of nonnegative numbers is LC-positive if for each r, the sequence of polynomials ∑n k=r a(n, k)q k is q-log-concave. It is double LC-positive if both triangles {a(n, k)} and {a(n, n − k)} are LC-positive. We show that if {a(n, k)} is LC-positive then the log-concavity of the sequence {xk} implies that of the sequence {zn} defined by zn = ∑n k=0 a(n, k)xk, and if {a(n, ...

We present different notions of convexity and concavity for copulas and we study the relationships among them.

We present in this paper a study of concavity detection using binary edge mask information, and consistency links between them. A model for a corner is proposed as a particular arrangement of edge masks. In a second step, we merge these corner in order to build concavities. Enclosures are obtained as a particular case of concavities. Examples are shown in the context of suburban area and more p...

An e ective algorithm for solving stochastic resource allocation problems is to build piecewise linear, concave approximations of the recourse function based on sample gradient information. Algorithms based on this approach are proving useful in application areas such as the newsvendor problem, physical distribution and eet management. These algorithms require the adaptive estimation of the app...