V. Borrelli et al., A GEOMETRIC CHARACTERIZATION OF THE WHITN EY SPHERE, Comptes rendus de l'Academie des sciences. Serie 1, Mathematique, 321(11), 1995, pp. 1485-1490
We prove that the local geometrical invariants of a Lagrangian submani
fold of C-n (the square of its mean curvature H-2 and its scalar curva
ture tau), satisfy the following fundamental inequality: H-2 greater t
han or equal to 2(n+2)/n(2)(n-1)tau. (We use for this purpose a partic
ular property of symmetry of the second fundamental form of Lagrangian
immersions.) The equality case allows to characterise the Whitney imm
ersion.