Rational sections of elliptic fibrations are known to gives rise to the abelian part of the gauge algebra in F-theory compactifications. In this talk I will focus on how the discrete structure of the Mordell—Weil lattice also encodes the global form of the full gauge group. Complex structure deformations that correspond to field theoretic (un-)higgsing further connects these ideas to F-theory on torus-fibrations with only multi-sections, which are believed to be hallmark of discrete abelian symmetries. Using an example constructed through the complex structure deformation, I will argue that we need to extend our current understanding of F-theory with multi-sections.

### Math-Physics Joint Seminar

Thursday, April 26, 2018 - 4:30pm

#### Ling Lin

University of Pennsylvania, Physics