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Federico Lo Bianco

Publications and source records attributed to Federico Lo Bianco.

6 recordsLinked to original sources
arXiv2024

An application of $p$-adic integration to the dynamics of a birational transformation preserving a fibration

Let $f\colon X \dashrightarrow X$ be a birational transformation of a projective manifold $X$ whose Kodaira dimension $κ(X)$ is non-negative. We show that, if there exist a meromorphic fibration $π\colon X\dashrightarrow B$ and a pseudo-automorphism $f_B\colon B\dashrightarrow B$ which preserves a big line bundle $L\in Pic(B)$ and such that $f_B\circ π=π\circ f$, then $f_B$ has finite order. As a corollary we show that, for projective irreducible symplectic manifolds of type $K3^{[n]}$ or generalized Kummer, the first dynamical degree characterizes the birational transformations admitting a Zariski-dense orbit.

math.AG↗
arXiv2020

Numerical characterization of some toric fiber bundles

Given a complex projective manifold $X$ and a divisor $D$ with normal crossings, we say that the logarithmic tangent bundle $T_X(-\log D)$ is R-flat if its pull-back to the normalization of any rational curve contained in $X$ is the trivial vector bundle. If moreover $-(K_X+D)$ is nef, then the log canonical divisor $K_X+D$ is torsion and the maximally rationally chain connected fibration turns out to be a smooth locally trivial fibration with typical fiber $F$ being a toric variety with boundary divisor $D_{|F}$.

math.AG↗
arXiv2019

On the cohomological action of automorphisms of compact Kähler threefolds

Extending well-known results on surfaces, we give bounds on the cohomological action of automorphisms of compact Kähler threefolds. More precisely, if the action is virtually unipotent we prove that the norm of $(f^n)^*$ grows at most as $cn^4$; in the general case, we give a description of the spectrum of $f^*$, and bounds on the possible conjugates over $\mathbb Q$ of the dynamical degrees $λ_1(f),λ_2(f)$. Examples on complex tori show the optimality of the results.

math.AG↗
arXiv2016

On the primitivity of birational transformations of irreducible symplectic manifolds

Let $f\colon X\dashrightarrow X$ be a bimeromorphic transformation of a complex irreducible symplectic manifold $X$. Some important dynamical properties of $f$ are encoded by the induced linear automorphism $f^*$ of $H^2(X,\mathbb Z)$. Our main result is that a bimeromorphic transformation such that $f^*$ has at least one eigenvalue with modulus $>1$ doesn't admit any invariant fibration (in particular its generic orbit is Zariski-dense).

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arXiv2015

Smooth foliations on homogeneous compact Kähler manifolds

We study smooth foliations of arbitrary codimension on homogeneous compact Kähler manifolds. We prove that smooth foliations on rational compact homogeneous manifolds are locally trivial fibrations and classify the smooth foliations with all leaves analytically dense on compact homogeneous Kähler manifolds. Both results are builded upon a (rough) structure Theorem for smooth foliations on compact homogeneous Kähler manifolds obtained by comparison of the foliation and the Borel-Remmert decomposition of the ambient.

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