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Sabir M. Gusein-Zade

Publications and source records attributed to Sabir M. Gusein-Zade.

43 records · Page 3Linked to original sources
arXiv2004

Multi-index filtrations and motivic Poincare series

The Poincare series of a multi-index filtration on the ring of germs of functions can be written as a certain integral with respect to the Euler characteristic over the projectivization of the ring. Here this integral is considered with respect to the generalized Euler characteristic with values in the Grothendieck ring of varieties. For the filtration defined by orders of functions on the components of a plane curve singularity $C$ and for the so called divisorial filtration for a modification of $(\C^2,0)$ by a sequence of blowing-ups there are given formulae for this integral in terms of an embedded resolution of the germ $C$ or in terms of the modification respectively. The generalized Euler characteristic of the extended semigroup corresponding to the divisorial filtration is computed.

math.AG↗
arXiv2003

A filtration defined by arcs on a variety

We define a natural filtration on the ring ${\cal O}_{V,0}$ of germs of functions on a germ of a complex analytic variety $(V,0)$ related with the geometry of arcs on the variety and describe some properties of it.

math.AG↗
arXiv2001

Indices of 1-forms on an isolated complete intersection singularity

There are some generalizations of the classical Eisenbud-Levine-Khimshashvili formula for the index of a singular point of an analytic vector field on $R^n$ for vector fields on singular varieties. We offer an alternative approach based on the study of indices of 1-forms instead of vector fields. When the variety under consideration is a real isolated complete intersection singularity (icis), we define an index of a (real) 1-form on it. In the complex setting we define an index of a holomorphic 1-form on a complex icis and express it as the dimension of a certain algebra. In the real setting, for an icis $V=f^{-1}(0)$, $f:(C^n, 0) \to (C^k, 0)$, $f$ is real, we define a complex analytic family of quadratic forms parameterized by the points $ε$ of the image $(C^k, 0)$ of the map $f$, which become real for real $ε$ and in this case their signatures defer from the "real" index by $χ(V_ε)-1$, where $χ(V_ε)$ is the Euler characteristic of the corresponding smoothing $V_ε=f^{-1}(ε)\cap B_δ$ of the icis $V$.

math.AG↗
arXiv1999

On A_k-singularity on a plane curve of fixed degree

Let $k(d)$ be the maximal possible integer $k$ such that there exists a plane curve of degree $d$ with an $A_k$--singularity. We construct a plane curve of degree $28s+9$ ($s\in\Z_{\ge 0}$) which has an $A_k$--singularity with $k=420s^2+269s+42$. Therefore one has $\underline{\lim}_{d\to\infty}k(d)/d^2\ge 15/28$ (pay attention that $15/28>1/2$).

math.AG↗
arXiv1998

On the index of a vector field at an isolated singularity

We consider manifolds with isolated singularities, i.e., topological spaces which are manifolds (say, $C^\infty$--) outside discrete subsets (sets of singular points). For (germs of) manifolds with, so called, cone--like singularities, a notion of the index of an isolated singular point of a vector field is introduced. There is given a formula for the index of a gradient vector field on a (real) isolated complete intersection singularity. The formula is in terms of signatures of certain quadratic forms on the corresponding spaces of thimbles.

alg-geom↗
arXiv1997

Zeta-functions for germs of meromorphic functions and Newton diagrams

For a germ of a meromorphic function f=P/Q, we offer notions of the monodromy operators at zero and at infinity. If the holomorphic functions P and Q are non-degenerated with respect to their Newton diagrams, we give an analogue of the formula of Varchenko for the zeta-functions of these monodromy operators.

math.CV↗