We consider the mean-variance (M-V) model of Markowitz and the construction of the risk-return efficient frontier. We examine the effects of applying buy-in thresholds, cardinality constraints and transaction roundlot restrictions to the portfolio selection problem. Such discrete constraints are of practical importance but make the efficient frontier discontinuous. The resulting quadratic mixed...

short-selling prohibition has been one of the primary assumptions of markowitz mean-variance model. solving markowitz quadratic model creates investment efficient frontier by considering only two return and budget constraints. in order to develop a more realistic portfolio selection model, in this paper, a new mathematical model is developed to allow short-selling under some practical constrain...

the structure and properties of niobapyrimidinium complex were examined by density functionaltheory method (mpw1pw91). the effect of solvent on the structural parameters, frontier orbitalenergies and hyperpolarizability (
tot) of this molecule has been explored. the thermodynamicproperties of the title compound at different temperatures have been calculated. also, the parasubstitutionseffect on...

We establish complexities of the conjunctive query entailment problem for classes of existential rules (i.e. Tuple-Generating Dependencies or Datalog+/rules). Our contribution is twofold. First, we introduce the class of greedy bounded treewidth sets (gbts), which covers guarded rules, and their known generalizations, namely (weakly) frontier-guarded rules. We provide a generic algorithm for qu...

The field of production frontier estimation is divided between the parametric Stochastic Frontier Analysis (SFA) and the deterministic, nonparametric Data Envelopment Analysis (DEA). This paper explores an amalgam of DEA and SFA that melds a nonparametric frontier with a stochastic composite error. Our model imposes the standard SFA assumptions for the inefficiency and noise terms. The frontier...

Consider a planar Brownian motion run for finite time. The frontier or “outer boundary” of the path is the boundary of the unbounded component of the complement. Burdzy (1989) showed that the frontier has infinite length. We improve this by showing that the Hausdorff dimension of the frontier is strictly greater than 1. (It has been conjectured that the Brownian frontier has dimension 4/3, but ...

This paper examines several extensions of the stochastic frontier that account for unmeasured heterogeneity as well as firm inefficiency. The fixed effects model is extended to the stochastic frontier model using results that specifically employ its nonlinear specification. Based on Monte Carlo results, we find that the incidental parameters problem operates on the coefficient estimates in the ...

The idea of the frontier reflects a uniquely colonial view of a place and process of encounter between colonising people, indigenous inhabitants, and natural landscapes.[1] Within this colonial context, the idea of the frontier has been variously developed through history by natural and social scientists, popular historians, artists, writers, and government officials. This volume draws together...