The volume minimizing problem of Lagrangian submanifolds in K\"ahler manifolds under Hamiltonian deformations was investigated first by Y. G. Oh about the beginning of 1990's. It is fundamental and interesting as a geometric variational problem related to Lagrangian submanifolds in In this talk we shall discuss a nice classe of Lagrangian submanifolds in complex hyperquadrics and their Hamiltonian stability problems. The complex hyperquadric is an Hermitian symmetric space of compact type and rank $2$ : $\widetilde{\mathrm Gr}_{2}({\bold R}^{n+2}) \cong Q_{n}({\bold C}) \cong SO(n+2)/SO(2)\times SO(n)$. The relationship of minimal Lagrangian submanifold in complex hyperquadrics with isoparametric hypersurfaces in spheres will be emphasized. We shall mention our recent results on the Hamilitonian stability/instability of compact minimal Lagrangian submanifold embedded in complex hyperquadrics obtained as the images of the Gauss maps of homogeneous isoparametric hypersurfaces in spheres.
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