2 papers
math.CO2026
Improved bounds for the double cap conjecture
Domonkos Czifra, Ãkos Dúcz, Máté Matolcsi +2
In 1974, Witsenhausen asked for the maximum possible density of a measurable subset of the unit sphere such that contains no p…
math.CO2025
A nonexistence criterion and new constructions for Butson Hadamard matrices
Domonkos Czifra, Máté Matolcsi, Ferenc SzöllÅsi
Based on the concept of positive definite functions on finite groups, we present a new necessary condition for the existence of Butson Hadamard matrices . We use this cond…