This paper considers the problem of when a local martingale is a martingale or a universally integrable martingale, for the case of time-homogeneous scalar diffusions. Necessary and suffcient conditions of a geometric nature are obtained for answering this question. These results are widely...

The Polish tax and benefit system is presented in the context of a recently developedmicrosimulation model, SIMPL. The model allows simulating direct taxes, social contributionsand public benefits in Poland for the years 2003 and 2005...>br>