Limits of Amao multiplicities and Epsilon multiplicity
Abstract
Let R be a d-dimensional Noetherian local ring with maximal ideal mR and let I be an ideal of R. The epsilon multiplicity ε(I) of I is defined by Ulrich and Validashti in \cite{UV} as a limsup of normalized lengths. We show in this paper that the epsilon multiplicity is always a limit of these normalized lengths. Specifically, ε(I)= limn→∞ ℓR((In)sat/In)/nd/d!. We prove that the epsilon multiplicity satisfies an associativity formula, analogous to that of the ordinary multiplicity. We prove these results by comparing the epsilon multiplicity to a suitable limsup of normalized Amao multiplicities, the Amao epsilon multiplicity aε(I). We show that the epsilon multiplicity is always equal to the Amao epsilon multiplicity, which is itself a limit.
Related
- Adversarial Multiplicity: Cherry-Picked Models and the Limits of Disclosure
- Exotic knot traces and the epsilon-invariant
- Topological line arrangements with high multiplicities
- Local Gan-Gross-Prasad conjecture for unitary groups: Trace formula approach for epsilon dichotomy
- New conjectures on multiplicities of tensor eigenvalues
BibTeX
@misc{cutkosky2026limits,
title = {{Limits of Amao multiplicities and Epsilon multiplicity}},
author = {Steven Dale Cutkosky},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.12238},
eprint = {2608.12238},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.12238},
}
RIS
TY - UNPB
TI - Limits of Amao multiplicities and Epsilon multiplicity
AU - Steven Dale Cutkosky
PY - 2026
DA - 2026/10/04
PB - arXiv
DO - 10.48550/arxiv.2608.12238
UR - https://arxiv.org/abs/2608.12238
AB - Let R be a d-dimensional Noetherian local ring with maximal ideal m_R and let I be an ideal of R. The epsilon multiplicity ε(I) of I is defined by Ulrich and Validashti in \cite{UV} as a limsup of normalized lengths. We show in this paper that the epsilon multiplicity is always a limit of these normalized lengths. Specifically, ε(I)= lim_n→∞ ℓ_R((I^n)^sat/I^n)/n^d/d!. We prove that the epsilon multiplicity satisfies an associativity formula, analogous to that of the ordinary multiplicity. We prove these results by comparing the epsilon multiplicity to a suitable limsup of normalized Amao multiplicities, the Amao epsilon multiplicity aε(I). We show that the epsilon multiplicity is always equal to the Amao epsilon multiplicity, which is itself a limit.
ER -