4 papers
math.RA2024
The Dynkin-Specht-Wever lemma and some associated constructions
Gyula Lakos
In the first part of the paper, some extensions of the classical Dynkin-Specht-Wever lemma are developed. In the second part, we extend Burgunder's splitting construction, and rela…
math.RA2024
The symmetric Poincaré-Birkhoff-Witt theorem and Dynkin-Magnus commutators
Gyula Lakos
The objective of this paper is to give alternative proofs for the symmetric Poincaré-Birkhoff-Witt theorem utilizing the Magnus recursion formulae or Dynkin's non-commutative polyn…
math.SP2023
Convergence estimates for the Magnus expansion IIA. matrices with operator norm
Gyula Lakos
We review and provide simplified proofs related to the Magnus expansion, and improve convergence estimates. Observations and improvements concerning the Baker--Campbell--Hausdorff…
math.SP2022
A short proof of the elliptical range theorem
Gyula Lakos
A short proof of the elliptical range theorem concerning the numerical range of complex matrices is given.