OWR-15178-020 · Complete realization theorem

Arbitrary Local-Cohomology Lengths between Consecutive Ideal Powers

Manuscript 24 October 2026 · Online 24 October 2026

math.ACUnrefereed preprint

Abstract

For every field k and every integer i >= 0, we construct a fixed complete regular local ring (R,m) of dimension 2i+2 and a fixed prime complete-intersection ideal I with the following property. Every sequence (a_n) of nonnegative integers is realized by ideals J_n satisfying I^(n+1) contained in J_n contained in I^n and length H^i_m(R/J_n) = a_n. All lower local cohomology vanishes, and all transition maps below degree i+1 are zero. Thus even adjacent-power bounds impose no asymptotic restriction on these lengths for arbitrary decreasing cofinal families. The construction inserts a one-column module presentation into each successive homogeneous layer; its length is computed directly in the top Cech module of a power-series ring. The families need not be multiplicative. The result concerns the unrestricted-family formulation and makes no assertion about ordinary, symbolic, or Frobenius powers. This is an unrefereed preprint prepared with AI assistance; no independent review, formal verification, or absolute priority certification is claimed.

Record

Affiliation
Mercury Software GmbH
Result
Complete realization theorem
Categories
math.AC
Manuscript
24 October 2026
Online release
24 October 2026
Version
1.0
License
Creative Commons Attribution 4.0 International

Files and verification

The PDF is the canonical reading copy. The source archive contains the LaTeX manuscript, bibliography, reproducibility material, and audit documents without build artefacts.

Citation

Alper Ferudun, “Arbitrary Local-Cohomology Lengths between Consecutive Ideal Powers,” EulerSolve Research Papers, OWR-15178-020, 2026. https://doi.org/10.5281/zenodo.23624056.

BibTeX
@misc{ferudun2026cohomologylengths,
  author = {Ferudun, Alper},
  title = {Arbitrary Local-Cohomology Lengths between Consecutive Ideal Powers},
  year = {2026},
  howpublished = {EulerSolve Research Papers},
  url = {https://eulersolve.org/papers/owr-15178-020/},
  doi = {10.5281/zenodo.23624056},
  note = {OWR-15178-020; unrefereed preprint}
}

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