Koszul pairs and applications

Autor: Javier López Peña, Pascual Jara, Dragoş Ştefan
Rok vydání: 2010
Předmět:
DOI: 10.48550/arxiv.1011.4243
Popis: Let $R$ be a semisimple ring. A pair $(A,C)$ is called almost-Koszul if $A$ is a connected graded $R$-ring and $C$ is a compatible connected graded $R$-coring. To an almost-Koszul pair one associates three chain complexes and three cochain complexes such that one of them is exact if and only if the others are so. In this situation $(A,C)$ is said to be Koszul. One proves that a connected $R$-ring $A$ is Koszul if and only if there is a connected $R$-coring $C$ such that $(A,C)$ is Koszul. This result allows us to investigate the Hochschild (co)homology of Koszul rings. We apply our method to show that the twisted tensor product of two Koszul rings is Koszul. More examples and applications of Koszul pairs, including a generalization of Fr\"oberg Theorem, are discussed in the last part of the paper.
Comment: The final version, accepted for publication in Journal of Noncommutative Geometry
Databáze: OpenAIRE