Heteroscedasticity and non-monotonic efficiency effects of a stochastic frontier model

We consider a model that provides flexible parameterizations of the exogenous influences on inefficiency. In particular, we demonstrate the model's unique property of accommodating non-monotonic efficiency effect. With this non-monotonicity, production efficiency no longer increases or decreases monotonically with the exogenous influence; instead, the relationship can shifts within the sample. Our empirical example shows that variables can indeed have non-monotonic effects on efficiency. Furthermore, ignoring non-monotonicity is shown to yield an inferior estimation of the model, which sometimes results in opposite predictions concerning the data.stochastic frontiers; heteroscedasticity; non-monotonic effects

Symmetrical Information and Credit Rationing: Graphical Demonstrations

As this article shows, the pro-debtor U.S. Bankruptcy Code alone can cause credit rationing, even without asymmetrical information in the market, because the code entails substantial costs to lenders if borrowers file for bankruptcy. In the absence of bankruptcy cost, lenders are always justified in raising interest rates and clearing markets. If the bankruptcy cost is nontrivial, however, lenders' profits are concave in the relevant range of interest rates. Thus, lenders cannot always clear the market by using higher rates. The study reported here also found that the use of collateral in debt contracts can reduce rationing but that even 100 percent collateral does not eliminate all rationing possibilities. A positive relationship was found between credit risk and the amount of pledged collateral, which is not necessarily true with models based on asymmetrical information.Company Failures; Credit Control; Debt

Brundan-Kazhdan-Lusztig and super duality conjectures

We formulate a general super duality conjecture on connections between parabolic categories O of modules over Lie superalgebras and Lie algebras of type A, based on a Fock space formalism of their Kazhdan-Lusztig theories which was initiated by Brundan. We show that the Brundan-Kazhdan-Lusztig (BKL) polynomials for Lie superalgebra gl(m|n) in our parabolic setup can be identified with the usual parabolic Kazhdan-Lusztig polynomials. We establish some special cases of the BKL conjecture on the parabolic category O of gl(m|n)-modules and additional results which support the BKL conjecture and super duality conjecture.Comment: v2, 44 pages, mild changes, clarifications on Introduction and other place

Character formulae in category O\mathcal O for exceptional Lie superalgebra G(3)G(3)

We classify the blocks, compute the Verma flags of tilting and projective modules in the BGG category $\mathcal O$ for the exceptional Lie superalgebra $G(3)$. The projective injective modules in $\mathcal O$ are classified. We also compute the Jordan-H\"older multiplicities of the Verma modules in $\mathcal O$.Comment: 28 page