Regular orbital measures on Lie algebras
Let H₀ be a regular element of an irreducible Lie algebra , and let be the orbital measure supported on . We show that if and only if k > dim /(dim - rank ).
Let H₀ be a regular element of an irreducible Lie algebra , and let be the orbital measure supported on . We show that if and only if k > dim /(dim - rank ).
In this Note, we define a class of stratified Lie groups of arbitrary step (that are called “groups of type ” throughout the paper), and we prove that, in these groups, sets with constant intrinsic normal are vertical halfspaces. As a consequence, the reduced boundary of a set of finite intrinsic perimeter in a group of type is rectifiable in the intrinsic sense (De Giorgi’s rectifiability theorem). This result extends the previous one proved by Franchi, Serapioni & Serra Cassano in step...