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
"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