Page "Antiparticle" Paragraph 15

where n < sup > c </ sup > denotes the charge conjugate state, i. e., the antiparticle.

This behaviour under CPT is the same as the statement that the particle and its antiparticle lie in the same irreducible representation of the Poincaré group.

Properties of antiparticles can be related to those of particles through this.

If T is a good symmetry of the dynamics, then