 Some authors have proposed radically different solutions to this puzzle.For example, propose that instead of twisted K-theory, II string theory configurations should be classified by elliptic cohomology.Prominent researchers in this area include Edward Witten, Peter Bouwknegt, Angel Uranga, Emanuel Diaconescu, Gregory Moore, Anton Kapustin, Jonathan Rosenberg, Ruben Minasian, Amihay Hanany, Hisham Sati, Nathan Seiberg, Juan Maldacena, Daniel Freed, and Igor Kriz.