The Caltech Geometry and Topology Seminar is pleased to sponsor the N+13th Southern California Topology Colloquium (SCTC). SCTC is a one-day conference primarily attended by mathematicians and scholars interested in topology and geometry, broadly defined, from the Southern California area. This year, the colloquium will be held on 

Saturday, October 17, 2026

@ California Institute of Technology

All talks will take place in 310 Linde Hall on the Caltech campus. 

See Logistics tab for locating the event venue, Wi-Fi, parking, travel, lodging information.

Registration: There is no registration fee, but you must register to attend. Register below:

Erica Flapan (Pomona College, CA, USA)

Qiuyu Ren (Stanford University, CA, USA)

Mayuko Yamashita (Perimeter Institute for Theoretical Physics, Waterloo, Canada)

Tian Yang (Texas A&M University, TX, USA)

All talks will take place at 310 Linde Hall. Food and drinks will be served in the lounge.

10:00-10:30: Registration & Breakfast and Coffee 

10:30-11:30: Erica Flapan

11:30-1:30: Lunch Break 

1:30-2:30: Qiuyu Ren 

2:30-2:50: Coffee Break

2:50-3:50: Tian Yang 

3:50-4:10: Coffee Break

4:10-5:10: Mayuko Yamashita 

5:10-5:20: Closing and Dinner Coordination

6:00: Dinner (Location: President Thai, Pasadena)

Speaker: Erica Flapan (Pomona College)

Title:  The Topology of Entangled Molecules

Abstract:  Spatial graph theory is the study of the topology of graphs embedded in R³ . It can be thought of as a generalization of knot theory, but it was actually motivated by chemists trying to understand the symmetries of flexible  molecules. In this talk, we will explain the role of spatial graph theory in  classifying the symmetries of molecular M¨obius ladders and other entangled synthetic molecules, and how questions about flexible molecules have  motivated results in topology.

Speaker: Qiuyu Ren (Stanford University)

Title: Some Constructions of Cosmetic Surgeries

Abstract: The cosmetic surgery conjecture for knots states that no nontrivial knot in S³ admits two Dehn surgeries that are orientation-preservingly homeomorphic. This conjecture, as well as several of its variants, has received considerable attention in recent years. In this talk, we discuss a construction of cosmetic surgeries which disproves certain variants of the cosmetic surgery conjecture, including Problem 1.12(d) in the K3 problem list.

Speaker: Mayuko Yamashita (Perimeter Institute for Theoretical Physics, Canada)

Title: Equivariant elliptic cohomology and supersymmetric quantum field theories

Abstract: In this talk, I will explain the recent development in the Segal-Stolz-Teichner (SST) paradigm. The SST paradigm is a set of ideas connecting stable homotopy theory, especially the theory of elliptic cohomology theory, with supersymmetric quantum field theories in physics. Thanks to the recent mathematical development of equivariant elliptic cohomology thoery, we are currently experiencing a great enrichment the SST paradigm. In the talk, I will illustrate this by explaining my previous work with Y.Lin on Topological Elliptic Genera, and ongoing work on dual symmetry in TMF with D.Gepner and H.Oguri.

Speaker: Tian Yang (Texas A&M University)

Title: Volume Conjecture and some recent progress

Abstract: In this talk, I will first give an overview of the Volume Conjecture, which connects two seeming different approaches to 3-dimensional topology – the hyperbolic geometry and the quantum invariants. Then I will talk about a recent joint work with Tianyue Liu, Shuang Ming, Xin Sun and BaojunWu, where we define a family of quantum invariants for hyperbolic 3-manifolds with cusp ends and with totally geodesic boundary from the representation theory of the a quantum group, called the modular double of U_qsl(2;R), and prove that asymptotically these new invariants behave exactly in the way that the Volume Conjecture predicted.