1,721,018 research outputs found
Optimality in a financial economy with restricted participation
No full textWe analyze an economy with inside financial assets and outside money. Households have differing restricted access on both types of assets and, according to a well-known approach, they use money to pay taxes. Since competitive equilibria are generically inefficient, we perform a Pareto improvability analysis through a monetary intervention. It results that, if the government modifies the amount of money endowments for just one consumer in period one, then Pareto improvements upon the market equilibrium are possible
Pseudoconvexity on a closed convex set: an application to a wide class of generalized fractional functions
Full text linkThe issue of the pseudoconvexity of a function on a closed set is addressed. It is proved that if a function has no critical points on the boundary of a convex set, then the pseudoconvexity on the interior guarantees the pseudoconvexity on the closure of the set. This result holds even when the boundary of the set contains line segments, and it is used to characterize the pseudoconvexity, on the nonnegative orthant, of a wide class of generalized fractional functions, namely the sum between a linear one and a ratio which has an affine function as numerator and, as denominator, the p-th power of an affine function. The relationship between quasiconvexity and pseudoconvexity is also investigated
On the supremum in linear fractional programming with respect to any closed unbounded feasible set
No full textCoercivity Concepts and Recession Function in Constrained Problems
No full textThe existence of minimum points for a real function f over a closed and unbounded set D is analyzed, focusing on the behavior of f along the so called recession directions of D. With this regard several new coercivity concepts are introduced together with an extension of the recession function. Relationships between coercivity and the behavior of the introduced recession function are studied, giving particular attention to their fundamental role in deriving optimality conditions. Necessary and sufficient conditions guaranteeing the existence of the minimum points are given as well as results related to the boundedness of the set of optimal solutions
On Generalized Linearity of Quadratic Fractional Functions
No full textQuadratic fractional functions are proved to be quasilinear if and only if they are pseudo-linear. For these classes of functions, some characterizations are provided by means of the inertia of the quadratic form and the behavior of the gradient of the function itself. The study is then developed showing that generalized linear quadratic fractional functions share a particular structure. Therefore it is possible to suggest a sort of "canonical form" for those functions. A wider class of functions Given by the sum of a quadratic fractional function and a linear one is also studied. In this case generalized linearity is characterized by means of simple conditions. Finally, it is deepened on the role played by generalized linear quadratic fractional functions in optimization problems
Mixed Type Duality for Multiobjective Optimization Problems with Set Constraints
No full textThe aim of this chapter is to propose some pairs of dual programs where the pri- mal is a vector problem having a feasible region defined by a set constraint, equality and inequality constraints, while the duals can be classified as “mixed type” ones. The duality results are proved under suitable generalized concavity properties. In this light, the role of different kinds of generalized concavity properties will be deepened on
Recent Developments on Applied Mathematics Workshop on the Occasion of the 65th Birthday of Alberto Cambini, Pisa, April 2006
No full textA note on scalar 'generalized' invexity
No full textThis paper aims to study how much “generalized” invex properties differ from invexity and to establish whether or not the use of more and more parameters and functionals in the definitions is really effective and helpful. In particular, both smooth and nonsmooth scalar functions are considered. As a conclusion, by means of some equivalence results not necessarily related to invexity, it is proved that several “generalized” invexity properties are actually equivalent to invexity, and that this happens in both the differentiable case and the nondifferentiable one. In other words, the introduction of parameters in defining scalar “generalized” invexity properties does not yield “a priori” any kind of generalization
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