Connecting classical and abstract theory of Friedrichs systems via trace operator (Q642829)

Summary: Based on recent progress in understanding the abstract setting for Friedrichs symmetric positive systems in [\textit{A. Ern}, Commun. Partial Differ. Equations 32, No. 2, 317--341 (2007; Zbl 1118.47003)] we continue our efforts to relate these results to the classical Friedrichs theory. Following the approach via the trace operator, we extend the results of [\textit{N. Antonić} and \textit{K. Burazin}, J. Differ. Equations 250, No. 9, 3630--3651 (2011; Zbl 1223.35117)] to situations where the important boundary field does not consist only of projections, allowing the treatment of hyperbolic equations, besides the elliptic ones.