Long story short , My wife now is a green card holder (japanese citizen) . we got married 2009 , and she got her green card march 2010 with 2 years expiration date .
And now (january 18,2011) me and my wife are living in JAPAN because of my job. We decided to give up her green card , because we understand that a green card holder can not leave more than 1 year outside usa and also we don't want to have problem in the future when we have a plan to visit usa . So , after she return her green card , can she still have her Social Security Number ? i filed tax JOINT on 2009 .
and when she want to visit usa in the future , can she go there with normal procedure like before ? or does she need special visa to enter usa ?