# Reduction to the 2.5D case

Let us consider an environment with the following set of conditions:

(i.e., there is no dependence on the second component of , and indexing is being omitted by obvious reasons) and

so the matrix contains only diagonal elements, and we introduced the notation

so det . It follows from the system given by Eq.(3.2) that

and

where and . The solution of the last equation is trivial and corresponds to

It follows further that

where

Recalling as two-dimensional vector one gets that
 (3.6)

In the case of a point source it follows that

which indicates that the parameter is proportional to the ray path.

Orlando Camargo Rodríguez 2012-06-21