Geometry of real Grassmanian manifolds. V

The curvature transform is calculated for the Grassmanian manifold $G^+_{2,4}$ with the help of the Riemannian decomposition $G^+_{2,4}\cong S^2\times S^2$. Together with the author's earlier results about almost geodesic submanifolds of $G^+_{p,n}$, this makes it possible to give the formula for the Riemannian curvature in $G^+_{p,n}$. This formula allows us to give a geometrical description of two-dimensional directions with maximal sectional curvature in $G^+_{p,n}$.