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Seshadri positive submanifolds of polarized manifolds

Lucian Bădescu, Mauro Beltrametti (2013)

Open Mathematics

Let Y be a submanifold of dimension y of a polarized complex manifold (X, A) of dimension k ≥ 2, with 1 ≤ y ≤ k−1. We define and study two positivity conditions on Y in (X, A), called Seshadri A-bigness and (a stronger one) Seshadri A-ampleness. In this way we get a natural generalization of the theory initiated by Paoletti in [Paoletti R., Seshadri positive curves in a smooth projective 3-fold, Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl., 1996, 6(4), 259–274] (which...

Simple exponential estimate for the number of real zeros of complete abelian integrals

Dmitri Novikov, Sergei Yakovenko (1995)

Annales de l'institut Fourier

We show that for a generic polynomial H = H ( x , y ) and an arbitrary differential 1-form ω = P ( x , y ) d x + Q ( x , y ) d y with polynomial coefficients of degree d , the number of ovals of the foliation H = const , which yield the zero value of the complete Abelian integral I ( t ) = H = t ω , grows at most as exp O H ( d ) as d , where O H ( d ) depends only on H . The main result of the paper is derived from the following more general theorem on bounds for isolated zeros occurring in polynomial envelopes of linear differential equations. Let f 1 ( t ) , , f n ( t ) , t K , be a fundamental system of real solutions...

Singular open book structures from real mappings

Raimundo Araújo dos Santos, Ying Chen, Mihai Tibăr (2013)

Open Mathematics

We define open book structures with singular bindings. Starting with an extension of Milnor’s results on local fibrations for germs with nonisolated singularity, we find classes of genuine real analytic mappings which yield such open book structures.

Singular principal G -bundles on nodal curves

Alexander Schmitt (2005)

Journal of the European Mathematical Society

In the present paper, we give a first general construction of compactified moduli spaces for semistable G -bundles on an irreducible complex projective curve X with exactly one node, where G is a semisimple linear algebraic group over the complex numbers.

Some consequences of perversity of vanishing cycles

Alexandru Dimca, Morihiko Saito (2004)

Annales de l’institut Fourier

For a holomorphic function on a complex manifold, we show that the vanishing cohomology of lower degree at a point is determined by that for the points near it, using the perversity of the vanishing cycle complex. We calculate this order of vanishing explicitly in the case the hypersurface has simple normal crossings outside the point. We also give some applications to the size of Jordan blocks for monodromy.

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