Department of

September 2019 October 2019 November 2019 Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 1 2 3 4 5 1 2 8 9 10 11 12 13 14 6 7 8 9 10 11 12 3 4 5 6 7 8 9 15 16 17 18 19 20 21 13 14 15 16 17 18 19 10 11 12 13 14 15 16 22 23 24 25 26 27 28 20 21 22 23 24 25 26 17 18 19 20 21 22 23 29 30 27 28 29 30 31 24 25 26 27 28 29 30

Monday, October 7, 2019

**Abstract:** This will be part one of two talks aimed at motivating higher topos theory from physics. In this talk we will give a brief history of classical obstructions for manifolds, then suddenly find ourselves naturally requiring tools from higher topos theory. In the end, we shall see how working with simplicial sheaves on Manifolds allows us to define (but more importantly compute) geometric characteristic classes.