Projective (co)representations

By taking into account spin rotations explicitly, QSym² is able to characterise spin symmetry in terms of projective representations or corepresentations of the prevailing group. This is achieved by an implementation that makes use of homotopy paths for elements of \(\mathsf{SU}(2)\) as described in Simon L. Altmann's book on Rotations, Quaternions, and Double Groups.

A brief summary of this method will be added to this site in the future.