3 papers
math.RA2026
Perron matrix semigroups
Vladimir Yu. Protasov
We consider multiplicative semigroups of real dxd matrices. A semigroup S is called Perron if each of its matrices has a Perron eigenvalue, i.e., an eigenvalue equal to the spectra…
math.NT2025
Unique expansions in number systems via refinement equations
Sergei V. Konyagin, Vladimir Yu. Protasov, Alexey L. Talambutsa
Using the subdivision schemes theory, we develop a criterion to check if any natural number has at most one representation in the -ary number system with a set of non-negative i…
math.NA2025
Chebyshev approximation by non-Chebyshev systems
Vladimir Yu. Protasov, Rinat Kamalov
We address the problem of the best uniform approximation by linear combinations of a finite system of functions. If the system is Chebyshev and the problem is unconstrained, then t…