arXiv subjects

Zhaobang Zhu

Publications and source records attributed to Zhaobang Zhu.

2 recordsLinked to original sources

arXiv2026

A Counterexample to the Gyarmati-Matolcsi-Ruzsa Conjecture

We provide a counterexample to the non-abelian Gyarmati-Matolcsi-Ruzsa conjecture. The construction comes from an equivalent maximal-coupling entropy inequality, for which a counterexample can be found in a lower-dimensional group. We give an explicit cardinality counterexample in $D_4^{14}$, the fourteenth direct power of the dihedral group of order $8$.

cs.IT↗

arXiv2026

From an entropic inequality for sums in abelian groups to the theorems of Ruzsa and Plünnecke

We give a direct information-theoretic proof of the Plünnecke--Ruzsa inequalities for finite subsets of abelian groups. The argument rests on an elementary coupling inequality proved by maximizing joint entropy, without tensor powers or asymptotic constructions. It also yields Ruzsa's sumset triangle inequality and an extension to non-abelian groups.

cs.IT↗