Reflection Symmetry - Mathematical Equivalents

Mathematical Equivalents

For each line or plane of reflection, the symmetry group is isomorphic with C_s (see point groups in three dimensions), one of the three types of order two (involutions), hence algebraically C₂. The fundamental domain is a half-plane or half-space.

In certain contexts there is rotational as well as reflection symmetry. Then mirror-image symmetry is equivalent to inversion symmetry; in such contexts in modern physics the term parity or P-symmetry is used for both.