One can present diagram in a scheme known as the reduced zone scheme in which values are restricted to their values in the first Brillouin zone. The energy band structure in such a scheme is discontinuous as the bands in the picture are folded back to the first zone using periodicity.
diagram in a scheme known as the 
values are restricted to their values in the first Brillouin zone. The energy band structure in such a scheme is discontinuous as the bands in the picture are folded back to the first zone using periodicity. 
