Admissibility criteria for normal traces and Cauchy fluxes

Abstract

We compare notions of admissible surfaces for Cauchy fluxes, formulated as understanding when the normal trace of the underlying stress field can be represented by a measure. If this field is unbounded, the problem of admissibility is necessitated by the fact that the normal trace need not admit a measure representation on every regular surface, but only on ``almost all'' such surfaces. We compare an approach based on a precise majorant introduced by Šilhavý (Arch. Ration. Mech. Anal. 116.3 (1991)) with a Minkowski-type condition introduced by Chen, Torres and the first author (Arch. Ration. Mech. Anal. 249.6 (2025)) by showing that, under mild geometric conditions, the former condition implies the latter. We also show, by means of an explicit construction, that the latter admissibility condition can allow for arbitrary measure concentrations as a normal trace.