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Graduate Student Geometry-Topology Seminar

Monday, April 3, 2017 - 3:15pm

Jackson (McFeeley) Goodman

University of Pennsylvania


University of Pennsylvania


A trisection is a way of writing a smooth 4-manifold as a union of 4-handlebodies with a specified intersection along 3-handlebodies, generalizing a Heegaard splitting.  The fundamental groups of the pieces, together with the inclusion maps, form a diagram called a group trisection.  We will see examples of these group trisections, and how they reflect the operations among manifold trisections, like connected sums and stabilization.  We will then sketch a proof that group trisections up to isomorphism, classify manifold trisections up to diffeomorphism, after an appropriate stabilization.