Abstract:
We compute some invariants based on Hilbert-Poincaré series associated to Milnor algebras. These computations involve some of the classical surfaces and 3-folds with different configurations of isolated singularities.
As a by-product of a recent result of E. Sernesi, we give examples of classical hypersurfaces which are (or are not) projectively rigid.
We also include a Singular program to compute these invariants and to decide if a singular projective hypersurface is nodal and projectively rigid.
Key Words: Projective hypersurfaces, singularities, Milnor algebra, Hilbert-Poincaré series, rigid hypersurface.
2010 Mathematics Subject Classification: Primary: 13D40;
Secondary: 14J70, 14Q10, 32S25.
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