Description: Define class of all star rings. A star ring is a ring with an
involution (conjugation) function. Involution (unlike say the ring
zero) is not unique and therefore must be added as a new component to
the ring. For example, two possible involutions for complex numbers are
the identity function and complex conjugation. Definition of involution
in Holland95 p. 204. (Contributed by NM, 22-Sep-2011)(Revised by Mario Carneiro, 6-Oct-2015)