Manifold maps commuting with the Laplacian
Manifold maps commuting with the Laplacian
The commutative algebra Q)(G\H) of isometry-invariant differential operators on a Riemannian symmetric space always contains the Laplace-Beltrami operator Δ.In fact, Δ is the generator of Q)(G\H) exactly when G/H is of rank one.Therefore it is natural to ask which manifold maps φ: G 1 /H 1 -+ G 2 /H …