Internalizing negative externalities in vehicle routing problems through green taxes and green tolls

Road freight transportation includes various internal and external costs that need to be accounted for in the construction of efficient routing plans. Typically, the resulting optimization problem is formulated as a vehicle routing problem in any of its variants. While the traditional focus of the vehicle routing problem was the minimization of internal routing costs such as travel distance or duration, numerous approaches to include external factors related to environmental routing aspects have been recently discussed in the literature. However, internal and external routing costs are often treated as competing objectives. This paper discusses the internalization of external routing costs through the consideration of green taxes and green tolls. Numeric experiments with a biased-randomization savings algorithm, show benefits of combining internal and external costs in delivery route planning.Peer Reviewe

On turning waves for the inhomogeneous Muskat problem: a computer-assisted proof

We exhibit a family of graphs that develop turning singularities (i.e. their Lipschitz seminorm blows up and they cease to be a graph, passing from the stable to the unstable regime) for the inhomogeneous, two-phase Muskat problem where the permeability is given by a nonnegative step function. We study the influence of different choices of the permeability and different boundary conditions (both at infinity and considering finite/infinite depth) in the development or prevention of singularities for short time. In the general case (inhomogeneous, confined) we prove a bifurcation diagram concerning the appearance or not of singularities when the depth of the medium and the permeabilities change. The proofs are carried out using a combination of classical analysis techniques and computer-assisted verification.Comment: 30 pages, 6 figure

El contexto de la democracia y la participación en el sistema capitalista

La siguiente reflexión analiza las estructuras y los elementos del Estado moderno, sus primeras manifestaciones, pasando por su evolución y los fundamentos teóricos que se le fueron sumando en el contexto de la democracia capitalista y sus diversas formas de expresión en las distintas sociedades. Ubicadas en el marco formal del Estado moderno encontramos al mercado político en el que aparecen tanto la teoría de la representatividad como los partidos políticos; organizaciones indispensables para efectuarla y sin los cuales sería difícil comprender la política en sus modalidades de interlocución, negociación y demandas sociales. En este sentido también se mencionan cuestiones referentes a la administración tecnocrática del Estado y la precisión de los marcos teóricos de algunos de sus principales representantes, así como las referentes a la construcción de la ingeniería social de la democracia