3,436 research outputs found
P-adic lattices are not K\"ahler groups
In this note we show that any lattice in a simple p-adic Lie group is not the
fundamental group of a compact Ka\"hler manifold, as well as some variants of
this result.Comment: Final versio
Oxidation resistant, thoria-dispersed nickel-chromium-aluminum alloy
Modified thoria-dispersed nickel-chromium alloy has been developed that exhibits greatly improved resistance to high-temperature oxidation. Additions of aluminum have been made to change nature of protective oxide scale entirely and to essentially inhibit oxidation at temperatures up to 1260 C
Symmetric differentials and the fundamental group
Esnault asked whether every smooth complex projective variety with infinite
fundamental group has a nonzero symmetric differential (a section of a
symmetric power of the cotangent bundle). In a sense, this would mean that
every variety with infinite fundamental group has some nonpositive curvature.
We show that the answer to Esnault's question is positive when the
fundamental group has a finite-dimensional representation over some field with
infinite image. This applies to all known varieties with infinite fundamental
group. Along the way, we produce many symmetric differentials on the base of a
variation of Hodge structures.
One interest of these results is that symmetric differentials give
information in the direction of Kobayashi hyperbolicity. For example, they
limit how many rational curves the variety can contain.Comment: 14 pages; v3: references added. To appear in Duke Math.
On the second cohomology of K\"ahler groups
Carlson and Toledo conjectured that any infinite fundamental group
of a compact K\"ahler manifold satisfies . We assume
that admits an unbounded reductive rigid linear representation. This
representation necessarily comes from a complex variation of Hodge structure
(\C-VHS) on the K\"ahler manifold. We prove the conjecture under some
assumption on the \C-VHS. We also study some related geometric/topological
properties of period domains associated to such \C-VHS.Comment: 21 pages. Exposition improved. Final versio
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