Using the bulk deformation of Floer cohomology by Schubert classes and non-Archimedean analysis of Fukaya–Oh–Ohta–Ono’s bulk-deformed potential function, we prove that every complete flag manifold () with a monotone Kirillov–Kostant–Souriau (KKS) symplectic form carries a continuum of nondisplaceable Lagrangian tori which degenerates to a nontorus fiber in the Hausdorff limit. In particular, the Lagrangian -fiber in is nondisplaceable, answering a question raised by Nohara and Ueda who computed its Floer cohomology to be vanishing.
In honor of Kenji Fukaya’s 60th birthday
Yunhyung Cho. Yoosik Kim. Yong-Geun Oh. "A critical point analysis of Landau–Ginzburg potentials with bulk in Gelfand–Cetlin systems." Kyoto J. Math. 61 (2) 259 - 304, June 2021. https://doi.org/10.1215/21562261-2021-0002