  We study the topological nature of both isotropic and anisotropic SU(N)
Thirring model. It is shown that in the isotropic model there exists the
special point where the system lives in the topological phase and that in the
anisotropic one which is obtained by introducing two coupling constants and has
U(1) symmetry, we present a simple mechanism of the dynamical topological phase
transition which takes place at the infinite energy scale.
