7-2【李天军】Existence of non-orientable Lagrangian surfaces

发布时间:2025-06-20来源:几何与物理研究中心中文网页浏览次数:10

报告人:李天军(明尼苏达大学)

时间:2025年7月2日16:00-17:00  

地点:物质科研楼C1124



We discuss the existence  of non-orientable  Lagragian surfaces in symplectic 4-manifolds. We first briefly review the orientable case which has been extensively studied. In the  non-orientable case,  given a mod 2 degree 2 homology class, three basic facts are

(i) it is always represented by a non-orientable Lagrangian surface, 

(ii) the complexity satisfies Audin's Mod 4 congruence, 

(iii) the complexity  increases by 4 via Givental's local surgery.

So a natural problem is to investigate the minimal complexity of such surfaces subject to Audin's congruence. We  investigate  this problem for  symplectic rational surfaces and   focus on the existence of Lagrangian projective planes. This is based on joint works with  Bo Dai, Chung-I Ho, Weiwei Wu and Shuo Zhang.