  The "projective lightcone limit" has been proposed as an alternative
holographic dual of an AdS space. It is a new type of group contraction for a
coset G/H preserving the isometry group G but changing H. In contrast to the
usual group contraction, which changes G preserving the spacetime dimension, it
reduces the dimensions of the spacetime on which G is realized. The obtained
space is a projective space on which the isometry is realized as a linear
fractional transformation. We generalize and apply this limiting procedure to
the "Hopf reduction" and obtain (n-1)-dimensional complex projective space from
(2n-1)-dimensional sphere preserving SU(n) symmetry.
