Binary mekso operator: group-theoretic conjugation (group action): maps inputs (X_{1, X} to X_{2^(-X}= \phi_{(X}. Default: X_{3 }= 1.

Assumes that the inverse of X_{2} is defined; inherits the group operator '*' (which is binary and left-groups/evaluates from the left) from context and assumes that it is defined for the given input pairs. X_{3} will typically be \pm 1. Negative 'exponents' denote inverses; an 'exponent' of 0 denotes the jdentity element for the group.