Optimal Sparsifiers for Abelian Cayley Graphs
Abstract
We prove that for every Cayley graph π’ over any finite abelian group G, there is a weighted Cayley graph with O(log |G|) generators that is a spectral sparsifier for π’. This bound is optimal. Applying our bound to the group G = π½2n, yields, as a corollary, O(n/Ξ΅2)-sized code sparsifiers for π½2-linear codes, improving on the work of Khanna, Putterman and Sudan (SODA'24) who obtained a similar result with an additional polylog(n) loss. Our proof is strongly inspired by a recent work of Reis and Rothvoss for the construction of β1-sparsifiers. Following their work, the abelian Cayley sparsification problem can be reduced to establishing a lower bound for the volume of a certain natural convex body. This volume bound follows from a short, elementary argument that relies on character symmetry.
Related
- Cayley graphs of abelian groups, circular colorings and discrete fundamental groups
- Fast robbers on abelian Cayley graphs and digraphs
- Isomorphisms of abelian Cayley graphs with their natural edge-colouring
- Exact Diameter Windows for Random Cayley Graphs on Odd-Order Abelian Groups
- A complete classification of perfect state transfer in Grover walks on abelian Cayley graphs
BibTeX
@misc{basu2026optimal,
title = {{Optimal Sparsifiers for Abelian Cayley Graphs}},
author = {Arpon Basu and Pravesh K. Kothari and Raghu Meka and Stefan Tudose},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2607.08261},
eprint = {2607.08261},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.08261},
note = {CC BY-SA 4.0},
}
RIS
TY - UNPB
TI - Optimal Sparsifiers for Abelian Cayley Graphs
AU - Arpon Basu
AU - Pravesh K. Kothari
AU - Raghu Meka
AU - Stefan Tudose
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2607.08261
UR - https://arxiv.org/abs/2607.08261
AB - We prove that for every Cayley graph π’ over any finite abelian group G, there is a weighted Cayley graph with O(log |G|) generators that is a spectral sparsifier for π’. This bound is optimal. Applying our bound to the group G = π½_2^n, yields, as a corollary, O(n/Ξ΅^2)-sized code sparsifiers for π½_2-linear codes, improving on the work of Khanna, Putterman and Sudan (SODA'24) who obtained a similar result with an additional polylog(n) loss. Our proof is strongly inspired by a recent work of Reis and Rothvoss for the construction of β_1-sparsifiers. Following their work, the abelian Cayley sparsification problem can be reduced to establishing a lower bound for the volume of a certain natural convex body. This volume bound follows from a short, elementary argument that relies on character symmetry.
ER -