Hochschild (Co)Homology Dimension

By Yang Han. 2004

62 citations recorded by the source corpus.

In 1989 Happel asked the question whether, for a finite‐dimensional algebra A over an algebraically closed field k, gl.dim A < ∞ if and only if hch.dim A < ∞. Here, the Hochschild cohomology dimension of A is given by hch.dim A := inf{n ∞ N0 | dim HHi (A) = 0 for i > n}. Recently Buchweitz, Green, Madsen and Solberg gave a negative answer to Happel's question. They found a family of pathological algebras Aq for which gl.dim Aq = ∞ but hch.dim Aq = 2. These algebras are pathological in many aspects. However, their Hochschild homology behaviors are not pathological any more; indeed one has hh.dim Aq = ∞ = gl.dim Aq. Here, the Hochschild homology dimension of A is given by hh.dim A := inf{n ∞ N0 | dim HHi(A) = 0 for i > n}. This suggests posing a seemingly more reasonable conjecture by replacing the Hochschild cohomology dimension in Happel's question with the Hochschild homology dimension: gl.dim A < ∞ if and only if hh.dim A < ∞ if and only if hh.dim A = 0. The conjecture holds for commutative algebras and monomial algebras. In the case where A is a truncated quiver algebra, these conditions are equivalent to the condition that the quiver of A has no oriented cycles. Moreover, an algorithm for computing the Hochschild homology of any monomial algebra is provided. Thus the cyclic homology of any monomial algebra can be read off when the underlying field is characteristic 0.

Subfields: Algebra and Number Theory, Geometry and Topology, Mathematical Physics

View Paper: https://www.semanticscholar.org/paper/2b2a7e7fb2e8681f877e87ca750e93d2ae4be24f

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In Algebra and Number Theory

  1. Yongyun Qin
  2. Yang Han

In Geometry and Topology

  1. Yongyun Qin
  2. Yang Han

In Mathematical Physics

  1. Yongyun Qin
  2. Yang Han

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