Publications [Acknowledgement]



Acknowledgement. The research presented in these publications has been sponsored by the National Science Foundation Grants DMS 97-06827, DMS 01-07428, DMS 01-07917, DMS 04-07704, DMS 07-07949, DMS FRG 07-57227, by the Office of Naval Research Grants N00014-91-J-1076, N00014-09-1-0385 and by other US Government Agencies.