# King's College London

## Quantitative results on continuity of the spectral factorization mapping

Research output: Contribution to journalArticle

L. Ephremidze, E. Shargorodsky, I. Spitkovsky

Original language English JOURNAL OF THE LONDON MATHEMATICAL SOCIETY-SECOND SERIES 22 Jul 2019 https://doi.org/10.1112/jlms.12258 E-pub ahead of print - 22 Jul 2019

20 pages

## Abstract

The spectral factorization mapping $F\to F^+$ puts a positive definite integrable matrix function $F$ having an integrable logarithm of the determinant in correspondence with an outer analytic matrix function $F^+$ such that $F = F^+(F^+)^*$ almost everywhere. The main question addressed here is to what extent $\|F^+ - G^+\|_{H_2}$ is controlled by $\|F-G\|_{L_1}$ and $\|\log \det F - \log\det G\|_{L_1}$.