organizers: Harry Chen (Utah), David Gabai (Princeton), Siddhi Krishna (Berkeley), Alison Tatsuoka (Princeton)
The goal of this seminar is, as Dave says, to "get dirty" with foliations; this means that we will get into the deep into the details of constructions and examples.
Some of my past work has focused on constructing taut foliations in Dehn surgeries along positive braid knots; this work was motivated by the L-space conjecture. In this talk, I'll explain -- in a LOT of detail! -- how to construct taut foliations in r-surgery along P(-2,3,7)=K, where r <9 = 2g(K)-1. I'll explain why braids are a good tool in this setting, and also explain some implications of the construction. I will assume that you know what branched surfaces, train tracks, and taut foliations are, but I'll try not to assume much more.
We showed with Fenley in https://arxiv.org/abs/2510.15176 (and with some additional work in progress j.w. Barthelme and Mann) that a pair of transverse foliations by Gromov hyperbolic leaves in a closed 3-manifold either intersects as a blow up of an Anosov flow, or it contains a (generalized) Reeb surface. I will present this result and show how the proof splits in two parts depending on how leaves intersect in the universal cover. I will explain some examples and the proof of one of the parts, showing that whenever a pair of leaves intersect in more than one connected component, then the intersection foliation must contain a Reeb annulus (and note that we do not know if this situation is actually possible in atoroidal manifolds). Sergio will explain the other case.