We explicitly describe germs
of strongly pseudoconvex nonspherical real-analytic hypersurfaces M at the
origin in ℂn+1 for which the group of local CR-automorphisms preserving
the origin has dimension d0(M) equal to either n2− 2n + 1 with n ≥ 2 or
n2− 2n with n ≥ 3. The description is given in terms of equations defining
hypersurfaces near the origin, which are written in the Chern–Moser normal form.
These results are motivated by the classification of locally homogeneous Levi
nondegenerate hypersurfaces in ℂ3 with d0(M) = 1,2 due to A. Loboda, and
they complement earlier joint work by V. Ezhov and the author for the case
d0(M) ≥ n2− 2n + 2.
Keywords
Chern–Moser normal forms, strongly pseudoconvex
hypersurfaces, local CR-automorphisms