Mate-Nevai-Totik theorem for Krein systems (Q2039330)

The author considers the half-line Dirac operator with square summable potential and proves that its solution is bounded in the \(L_2\)-Cesàro sense for almost every real value of the eigenvalue parameter. To this end, he derives a convergence theorem for Krein systems, which can be seen as an analog of a 1991 result by \textit{A. Máté} et al. [Ann. Math. (2) 134, No. 2, 433--453 (1991; Zbl 0752.42015)].