**Title:** The Legendre transform and symmetries on the space of Kahler metrics

**Program Website:** Large N Limit Problems in Kahler Geometry

**Speaker:** Bo Berndtsson, Chalmers University of Technology

**Date:** Friday, April 24, 2015

**Time:** 2:00pm – 3:00pm

**Place:** Seminar Room 313, Simons Center

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**Title:** Hele-Shaw flow and holomorphics discs, I

**Program Website:** Large N Limit Problems in Kahler Geometry

**Speaker:** David Witt-Nystrom, Cambridge

**Date:** Friday, April 24, 2015

**Time:** 1:00pm – 2:00pm

**Place:** Seminar Room 313, Simons Center

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**Abstract:** Min-max methods were introduced in Geometry by Birkhoff in the 1910’s. Recently the theory has been used to solve several long standing open questions in Geometry and Topology. I will survey these developments and mention some new results.

**Title:** A Topologist looks at Sheaf Theory

**Program Website:** Interactions of Homotopy Theory and Algebraic Topology with Physics through Algebra and Geometry

**Speaker:** John Morgan

**Date:** Friday, December 19, 2014

**Time:** 02:45pm – 04:15pm

**Place:** Seminar Room 313, Simons Center

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**Abstract:** Sheaf theory has long been an essential tool in algebraic geometry, algebraic number theory, and complex analysis, but its inspiration comes directly from topology. This lecture course will emphasize these roots, hopefully making sheaf theory seem natural to those with a topological bent. The course will begin by covering the basic topics in sheaf theory describing the objects and the four basic maps of the theory and then will culminate with a discussion of Verdier duality, which generalizes Poincare duality.

This theory will then be applied to define a bordism theory, called duality bordism, whose coefficient group agrees with the Grothendieck group of chain complexes satisfying Poincare duality modulo those that sit as the boundary term in an exact sequence satisfying Lefschetz duality. This bordism group is the Pontryjagin dual homology theory to the cohomology theory associated with surgery theory. This means that a surgery problem is completely classified by evaluating surgery obstructions (signatures, and Arf invariants) of its restrictions to all possible duality bordism elements.

Direct analysis of this bordism theory allows one to identify it at odd primes with real K-theory and at the prime 2 with ordinary homology.

]]>**Title:** Summary of the Program and Closing Remarks

**Program:** Gauge Theory, Integrability, and Novel Symmetries of Quantum Field Theory

**Speaker:** Samson Shatashvili, SCGP

**Date:** Thursday, DEcember 18, 2014

**Time:** 11:00am – 12:00pm

**Place:** Seminar Room 313, Simons Center

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**Title:** Explorations in the Physics and Mathematics of Moonshine

**Speaker:** Shamit Kachru, Stanford

**Date:** Tuesday, November 25, 2014

**Time:** 04:15pm – 05:15pm

**Place:** Auditorium 103, Simons Center

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View the Slides.

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**Abstract:** “Monstrous moonshine” is a beautiful phenomenon first discovered in the 1980s, providing startling and unexpected relations between several fundamental objects in mathematics and the physics of a (rather peculiar) string theory. Very recently, physicists and mathematicians have started to uncover evidence of deep analogous “moonshine” connections between some of the more physically interesting solutions to string theory and important structures in group theory and number theory. In this talk, I describe in an elementary way some of the fundamental mathematical and physical objects implicated in the moonshine conjectures, and the surprising and as yet mysterious connections between them.

**Title:** Superspace Harmonic Analysis for Physicists

**Program:** Gauge Theory, Integrability, and Novel Symmetries of Quantum Field Theory

**Speaker:** Volker Schomerus, DESY

**Date:** Thursday, September 11, 2014

**Time:** 11:00am – 12:00pm

**Place:** Seminar Room 313, Simons Center

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**Title:**

**Program:** G2 Manifolds Program Seminar

**Speaker:** Tommaso Pacini, Scuola Normale Superiore di Pisa

**Date:** Thursday, September 11, 2014

**Time:** 11:00am – 12:00pm

**Place:** Lecture Hall 102, Simons Center

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**Title:**

**Program:** G2 Manifolds Program Seminar

**Speaker:** Mark Haskins, Imperial College

**Date:** Thursday, September 11, 2014

**Time:** 9:30am – 10:30pm

**Place:** Lecture Hall 102, Simons Center

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**Title:**

**Program:** G2 Manifolds Program Seminar

**Speaker:** David Morrison, UC Santa Barbara

**Date:** Wednesday, September 10, 2014

**Time:** 1:00pm – 2:00pm

**Place:** Seminar Room 313, Simons Center

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