# mapping class group

Since the set of diffeomorphisms of a manifold which are diffeotopic (http://planetmath.org/Diffeotopy) to the identity is a normal subgroup of the group of all diffeomorphisms, we can form the quotient of the diffeomorphism group by this subgroup. This quotient is known as the mapping class group.

Title mapping class group MappingClassGroup 2013-03-22 14:52:51 2013-03-22 14:52:51 rspuzio (6075) rspuzio (6075) 5 rspuzio (6075) Definition msc 57R50