  Almost all materials are anisotropic. In this paper, interface relations of
anisotropic elliptic partial differential equations involving discontinuities
across interfaces are derived in two and three dimensions. Compared with
isotropic cases, the invariance of partial differential equations and the jump
conditions under orthogonal coordinates transformation is not valid anymore. A
systematic approach to derive the interface relations is established in this
paper for anisotropic elliptic interface problems, which can be important for
deriving high order accurate numerical methods.
