The principal components are not directly accessible because
() is not known. However, projections onto the components can be computed

(Schölkopf et al., 1998b).
A projection *f* of a pattern in the original space onto a principal component in feature space can be computed as follows:

f = ()^{T} = k(,) . |
(2.30) |

The computational load for each projection onto a principal component is high,

2005-03-22