Parametrizations of unitary matrices and related coset spaces
Alan Macfarlane · Journal of Mathematical Physics · 1980
Explicit forms of U3 and U4 matrices as functions of a single adjoint vector are displayed. Parametrizations of the coset spaces U(N+r)/(UN×Ur) are discussed, most explicitly for r=1 and 2, and related, for N=3 and 4, to the results for U3 and U4 matrices.