Numerical and analytical results for the transportation problem of Monge-Kantorovich

The Monge-Kantorovich transportation problem has a long and interesting history and has found a great variety of applications (see Rachev and Rüschendorf (1998a,b)). Some interesting characterizations of optimal solutions to the transportation problem (resp. coupling problems) have been found recently. For the squared distance and discrete distributions they relate optimal solutions to generalized Voronoi diagrams. Numerically we investigate the dependence of optimal couplings on variations of the coupling function. Numerical results confirm also a conjecture on optimal couplings in the one-dimensional case for nonconvex coupling functions. A proof of this conjecture is given under some technical conditions. Received: November 1999     

Der Lehrstuhl für Allgemeine Betriebswirtschaftslehre — insbesondere Rechnungswesen und Controlling — der Helmut-Schmidt-Universität,Universität der Bundeswehr Hamburg

Ohne Zusammenfassung     

Rater Bias and Incentive Provision

The tendency of supervisors to judge an employee as either good or bad and then to seek out evidence supporting that earlier established opinion is regarded as one of the major problems of performance appraisal. We investigate the implications of this rater bias in a dynamic moral hazard model with a wealth‐constrained agent. Although rater bias weakens the agent's incentives to exert effort in late periods, at the same time it strengthens implicit incentives in early periods. Under the optimal contract, as long as rater bias is not overly strong, its adverse effect on late‐period incentives is fully offset by exploitation of stronger early‐period incentives and thereby leaves the principal's profits unchanged.