The first Hochschild cohomology group of a schurian cluster-tilted algebra

Given a cluster-tilted algebra B we study its first Hochschild cohomology group HH1(B) with coefficients in the B-B-bimodule B. We find several consequences when B is representation-finite, and also in the case where B is cluster-tilted of type Ã.Fil: Assem, Ibrahim. University of Sherbrooke; CanadáFil: Redondo, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Matemática Bahía Blanca. Universidad Nacional del Sur. Departamento de Matemática. Instituto de Matemática Bahía Blanca; Argentin

Modules over cluster-tilted algebras determined by their dimension vectors

We prove that indecomposable transjective modules over cluster-tilted algebras are uniquely determined by their dimension vectors. Similarly, we prove that for cluster-concealed algebras, rigid modules lifting to rigid objects in the corresponding cluster category are uniquely determined by their dimension vectors. Finally, we apply our results to a conjecture of Fomin and Zelevinsky on denominators of cluster variables.Comment: 9 page

On substitution algebras of permutations

The subject of this paper is a simulation to that in [1] but here we consider substitutions corresponding to transpositions instead of replacements.Comment: arXiv admin note: substantial text overlap with arXiv:1302.304

Debt and Corporate Performance: Evidence from Unsuccessful Takeovers

This paper examines how debt affects firms following failed takeovers. Using a sample of 573 unsuccessful takeovers, we find that, on average, targets significantly increase their debt levels. Targets that increase their debt levels more than the median amount reduce their levels of capital expenditures, sell off assets, reduce employment, increase focus and increase their operating cash flows. These leverage-increasing targets also realize superior stock price performance over the five years following the failed takeover. In contrast, those firms that increase their leverage the least show insignificant changes in their level of investment and their operating cash flows and realize stock price performance that is no different than their benchmarks. Those failed targets that increase their leverage the least, and fail to get taken over in the future, realize significant negative stock returns following their initial failed takeovers. The evidence is consistent with the hypothesis that debt helps firms remain independent not because it entrenches managers, but because it commits the manager to making the improvements that would be made by potential raiders.