Deformation, differentiable and symplectic equivalence for algebraic surfaces

 

 

Fabrizio Catanese

Bayreuth, Germany

 


Abstract

In the talk I will report about joint work with B. Wajnryb. First on the results which we already obtained, showing that even in the case of simply connected minimal algebraic surfaces of general type, deformation

and differentiable equivalence do not coincide.

 

 Exhibiting the simple families of abc surfaces which are not deformation equivalent, and proving their

diffeomorphism, we get a counterexample to a weaker form of the speculation DEF = DIFF of R. Friedman and J. Morgan, i.e., in the case where (by M. Freedman's theorem) the topological type is completely determined by the numerical invariants of the surface.

 

The methods of proof are rather general, but if we want to investigate the natural symplectic structures associated to the canonical class, the question of symplectic equivalence becomes more subtle in the

1-connected case. I will explain also work in progress on this second question, especially some beautiful geometry of discriminant curves.