On non-displaceable Lagrangian submanifolds in two-step flag varieties

Yoosik Kim

We prove that the two-step flag variety $\mathcal{F}\ell (1,n;n+1)$ carries a non-displaceable and non-monotone Lagrangian Gelfand--Zeitlin fiber diffeomorphic to $S^3 \times T^{2n-…