Let M be a closed, oriented, smooth 4-manifold with intersection form Γ, A(Γ) the automorphism group of Γ and D(M) the subgroup induced by orientation-preserving diffeomorphisms of M. In this note we study the question when D(M) is of infinite index in A(Γ) for a symplectic 4-manifold.
Bibliographical noteFunding Information:
The authors appreciate useful discussions with Scot Adams. The research for the first named author is partially supported by NSFC Grant 10990013 and 11371211 . The research for the second named author is partially supported by NCTS and NSC postdoctoral fellowship. The research for the third named author is partially supported by NSF .
- Automorphism groups
- Symplectic manifolds