Flexible Surfaces in $\mathbb{C}{P}^2$ and $S^2\times S^2$

Abstract

A surface $\Sigma$ in a 4-manifold $M$ is called flexible if any mapping class of the surface arises as the restriction of a diffeomorphism $(M,\Sigma )\to (M,\Sigma )$. We construct flexible surfaces in $\mathbb{C}{P}^2$ and $S^2\times S^2$ within any prescribed non-characteristic homology class. Within characteristic homology classes there is a spin structure obstructing flexibility and we construct so-called spin-flexible representatives.

arXiv comment19 pages, 9 figures. Comments welcome!