Singularities of Varieties
Singularities of Varieties
Singularities of Varieties
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Algebraic Criterion<br />
f ∈ D m,n is infinitesimally stable iff the the quotient <strong>of</strong> R[[x 1 ,...,x m ]] n<br />
by the module generated by the partial derivatives and by f i e j , where f i is<br />
the i-th coordinate <strong>of</strong> f and e j is the j-th unit vector, is generated by the<br />
unit vectors over R.<br />
Example (x, y) ↦→ (x 3 + xy, y).<br />
VO AAG 31