Growth in the minimal injective resolution of a local ring

  title={Growth in the minimal injective resolution of a local ring},
  author={Lars Winther Christensen and Janet Striuli and Oana Veliche},
  journal={Journal of the London Mathematical Society},
Let R be a commutative noetherian local ring with residue field k and assume that it is not Gorenstein. In the minimal injective resolution of R, the injective envelope E of the residue field appears as a summand in every degree starting from the depth of R. The number of copies of E in degree i equals the k‐vector space dimension of the cohomology module ExtiR(k, R). These dimensions, known as Bass numbers, form an infinite sequence of invariants of R about which little is known. We prove that… 
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