Rigidity and holomorphic Segre transversality for holomorphic Segre maps

Let and denote the complexifications of Heisenberg hypersurfaces in and , respectively. We show that non-degenerate holomorphic Segre mappings from into with possess a partial rigidity property. As an application, we prove that the holomorphic Segre non-transversality for a holomorphic Segre map from into with propagates along Segre varieties. We also give an example showing that this propagation property of holomorphic Segre transversality fails when N > 2n − 2.     

A rigidity theorem for holomorphic generators on the Hilbert ball

We present a rigidity property of holomorphic generators on the open unit ball of a Hilbert space . Namely, if is the generator of a one-parameter continuous semigroup on such that for some boundary point , the admissible limit - , then vanishes identically on .

     

A note on topological degree theory for holomorphic maps

Using degree theory, an elementary topological proof is given of some well-known results in the theory of several complex variables. In particular it is shown that a compact analytic variety consists of finitely many points. This research was supported in part by the Office of Naval Research under contract N00014-670-A-0128-0023. Reproduction in whole or in part is permitted for any purpose of the U.S. Government.     

A rigidity result for highest order local cohomology modules

Let M be a finitely generated faithful module over a noetherian ring R of dimension d < ￥ \infty and let \mathfrak a \subseteqq R {\mathfrak a} \subseteqq R be an ideal. We describe the (finite) set Supp_R(H_{\mathfrak a}^d (M)) = Ass_R(H_{\mathfrak a}^d (M)) \textrm{Supp}_R(H_{\mathfrak a}^d (M)) = \textrm{Ass}_R(H_{\mathfrak a}^d (M)) of primes associated to the highest local cohomology module H_{\mathfrak a}^d (M) H_{\mathfrak a}^d (M) in terms of the local formal behaviour of \mathfrak a {\mathfrak a} . If R is integral and of finite type over a field, Supp_R(H_{\mathfrak a}^d (M)) \textrm{Supp}_R(H_{\mathfrak a}^d (M)) is the set of those closed points of X = Spec(R) whose fibre under the normalization morphism n: X￠? X \nu : X' \rightarrow X contains points which are isolated in n^-1(Spec(R/\mathfrak a)) \nu^{-1}(\textrm{Spec}(R/{\mathfrak a})) .     

Jessen's theorem for holomorphic almost periodic maps

An analog of Jessen's theorem on the existence of a Jessen function and its relation to the distribution of roots of a holomorphic almost periodic function in a strip is obtained for almost periodic maps.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 8, pp. 1094–1107, August, 1990.     

Asplund operators and holomorphic maps

LetE andF be locally convex topological vector spaces. A holomorphic mapf: E→F is defined to be an Asplund map if it takes the separable subsets of a neighbourhood of eacha∈E into absolutely convex weakly metrisable subsets ofF; a Banach space is an Asplund space if and only if its identity map has this property. We show that a continuous linear map from a quasinormable locally convex spaceE into a Banach spaceF is an Asplund map if and only if it factors through an Asplund space. IfE andF are both Banach spaces, then a holomorphic mapf: E→F is an Asplund map if and only if its derivative maps factor through Asplund spaces for eacha∈E. This is true if and only if such a factorisation holds ata=0. Part of this research was done during a visit to the University of Namibia, whose financial support is gratefully acknowledged This article was processed by the author using the Springer-Verlag T_EX mamath macro package 1990     

Fibre cycles of holomorphic maps

On leave from: Mathematisches Institut, Bunsenstrasse 3-5, D-37073, Göttingen, Germany     

Commuting holonomies and rigidity of holomorphic foliations

In this article we study deformations of a holomorphic foliationwith a generic non-rational first integral in the complex plane.We consider two vanishing cycles in a regular fiber of the firstintegral with a non-zero self intersection and with vanishingpaths that intersect each other only at their start points.It is proved that if the deformed holonomies of such vanishingcycles commute then the deformed foliation has also a firstintegral. Our result generalizes a similar result of Ilyashenkoon the rigidity of holomorphic foliations with a persistentcenter singularity. The main tools of the proof are Picard–Lefschetztheory and the theory of iterated integrals for such deformations.     

A general approach to index theorems for holomorphic maps and foliations

Let M be a smooth complex manifold, and S(⊂ M) be a compact irreducible subvariety with dim _C S > 0. Let be given either a holomorphic map f : M → M with f _|S  = id _S , f ≠ id _M , or a holomorphic foliation on M: we describe an approach that can be applied to both map and foliation in order to obtain index theorems. Partially supported by GNSAGA, Centro de Giorgi, M.U.R.S.T.     

Primitive holomorphic maps of curves

Let t: XY be a proper morphism of non-singular irreducible affine curves over . This paper shows that there is seldom a holomorphic function f such that (t,f): X Y × is a holomorphic embedding.     

Fibre cycles of holomorphic maps

This and the second part of the paper are to a great extent parts of my thesis [Si] which also appeared as preprint Mathematica Gottingensis 5/92. This work was partly supported by the S7B170 Geometrie und Analysis in Göttingen     

A rigidity result for biharmonic functions clamped at a corner

LetC be a curve which is conformal to a pair of line segments meeting at an angle strictly between 0 and ,u a biharmonic function analytic in a neighbourhood ofC, whose gradient vanishes onC. It is shown thatu(x, y) must be constant.     

A note on holomorphic maps with unipotent Jacobian matrices

We prove that a holomorphic map is invertible if its Jacobian matrix is unipotent.