|Enlightened||First to answer and accepted with score of 10 or more. This badge can be awarded multiple times.|
Urs Schreiber earned this badge 3 times
jan 11 at 17:54Is ghost-number a physical reality/observable?
may 4 '12 at 21:11Sympletic structure of General Relativity
may 4 '12 at 21:11Physical interpretation of different selfadjoint extensions