Physics predicts the existence of a novel class of smooth invariants of 4-manifolds valued in the ring of topological modular forms. In this talk, we will describe general properties of this new invariant and consider some examples.
Links:
[1] http://www.mpim-bonn.mpg.de/de/taxonomy/term/39
[2] http://www.mpim-bonn.mpg.de/de/node/3444
[3] http://www.mpim-bonn.mpg.de/de/node/9096