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Pedro Barbassa

Publications and source records attributed to Pedro Barbassa.

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Stacky geometry and logarithmic topology of transversely affine foliations

We study the stacky and logarithmic-topological structures associated with transversely affine affine foliations. To such a foliation we attach its holonomy group and the corresponding quotient stack, which provides the natural geometric base for the multiplicative developing coordinate. Holomorphic and meromorphic reparametrisations are then identified with endomorphisms of this stack and of its compactification, yielding a geometric Singer-type theorem. We then classify these reparametrisations according to the geometry of the holonomy group. On the logarithmic-topological side, we pass to the Kato-Nakayama space, where the residues define canonical boundary characters, govern the induced linear dynamics on the boundary tori, and give rise to a canonical logarithmic lift of the developing map. In this way, the quotient stack controls the linear part of the theory, while the Kato-Nakayama space captures its logarithmic-topological and dynamical content.

math.AG

Distributions with Unstable Tangent Sheaf on $\mathbb{P}^3$

We study codimension one distributions on the projective three-space, focusing on cases where the tangent sheaf of the distribution is nonsplit and unstable. We relate the order of nonstability to the degree of the induced subfoliation by curves, showing that the order of nonstability is bounded. Moreover, we classify the tangent sheaf of the codimension one distributions that admit a subfoliation by curves of degree 1. In other words, assuming the sheaf is nonsplit, we classify the situations in which the tangent sheaf attains the maximal possible order of nonstability.

math.AG