Remarks on effective curvature
This is a theme from the geometric theory of diffraction. Wave propagation near the reflecting smooth boundary \(\Gamma\) of a two- dimensional domain depends on the so-called effective curvature. If all rays are tangent to \(\Gamma\), the effective curvature is shown to be given by the ordinary curvature of \(\Gamma\) minus the ray curvature at the point of tangency. The author further proves the coordinate invariance of the ray curvature in the case of a two-dimensional Riemannian space.
scientific article; zbMATH DE number 4214849