Shun-ichi Amari Hyeyoung Park Tomoko Ozeki Singularities Affect Dynamics of Learning in Neuromanifolds. 1007-1065 2006 18 Neural Computation 5 http://dx.doi.org/10.1162/neco.2006.18.5.1007 db/journals/neco/neco18.html#AmariPO06