Exploració per autor "Barja Yáñez, Miguel Ángel"
Ara es mostren els items 29-48 de 48
-
On a conjecture of Fujita
Barja Yáñez, Miguel Ángel (2000)
Article
Accés obert -
On the bicanonical map of irregular varieties
Barja Yáñez, Miguel Ángel; Lahoz Vilalta, Martí; Naranjo del Val, Joan Carles; Pareschi, Giusseppe (2010-02)
Report de recerca
Accés obertFrom the point of view of uniform bounds for the birationality of pluricanonical maps, irregular varieties of general type and maximal Albanese dimension behave similarly to curves. In fact Chen-Hacon showed that, at least ... -
On the slope of bielliptic fibrations
Barja Yáñez, Miguel Ángel (1997)
Article
Accés obertLet $\pi :S\longrightarrow B$ be a bielliptic fibration. We prove $S$ is, up to base change, a rational double cover of an elliptic fibration and that $\pi $ is isotrivial provided it is smooth. Finally, we prove that the ... -
On the slope of fibred surfaces
Barja Yáñez, Miguel Ángel; Zucconi, Franco (2000)
Article
Accés obertWe give an asymptotically sharp lower bound for the slope $\lambda (f)$ of a fibration $f:S\longrightarrow B$, where $S$ is a surface and $B$ is a curve, if there exists an involution on the general fibre $F$ of $f$. ... -
On the slope of fibred surfaces
Barja Yáñez, Miguel Ángel; Zucconi, Franco (1998)
Article
Accés obert -
On the slope of fibred threefolds
Barja Yáñez, Miguel Ángel (1998)
Article
Accés obertWe study from a geographical point of wiew fibrations of threefolds over smooth curves $f: T \longrightarrow B$ such that the general fibre is of general type. We prove the non-negativity of certain relative invariants under ... -
On the topological index of irregular surfaces
Barja Yáñez, Miguel Ángel; Naranjo, J. C.; Pirola, Gian Pietro (2005)
Article
Accés obertWe study the topological index of some irregular surfaces that we call generalized Lagrangian. We show that under certain hypotheses on the base locus of the Lagrangian system the topological index is non-negative. For ... -
Positivity properties of relative complete intersections
Barja Yáñez, Miguel Ángel; Stoppino, Lidia (2014-10)
Report de recerca
Accés obertWe give conditions for f-positivity of relative complete intersections in projective bundles. We also derive an instability result for the fibres. -
Slope inequalities for fibrations of non-maximal Albanese dimension
Barja Yáñez, Miguel Ángel (2021-06-15)
Article
Accés obertWe study and obtain Slope inequalities for fibred irregular varieties of non-maximal Albanese dimension. We give a comparison theorem between Clifford–Severi and Slope inequalities for this type of fibrations. We also ... -
Slope inequalities for higher dimensional irregular fibrations
Barja Yáñez, Miguel Ángel (2022-07-28)
Article
Accés restringit per política de l'editorialWe prove the equivalence between Clifford-Severi inequalities for good classes of varieties of maximal Albanese dimension and Slope Inequalities for such varieties fibred over curves. This provides a big set of new Slope ... -
Stability and singularities of relative hypersurfaces
Barja Yáñez, Miguel Ángel; Stoppino, Lidia (2014-07-30)
Report de recerca
Accés obertWe study relative hypersurfaces, and prove an instability condition for the fibres. This is the starting point for an investigation of the geometry of effective divisors on relative projective bundles. -
Surfaces on the Severi line
Barja Yáñez, Miguel Ángel; Pardini, Rita; Stoppino, Lidia (2016-05-01)
Article
Accés obertLet S be a minimal complex surface of general type and of maximal Albanese dimension; by the Severi inequality one has K-S(2) >= 4 chi(O-S). We prove that the equality K-S(2) = 4 chi(O-S) holds if and only if q(S) := ... -
The eventual paracanonical map of a variety of maximal Albanese dimension
Barja Yáñez, Miguel Ángel; Pardini, Rita; Stoppino, Lidia (2019)
Article
Accés obertLet Xbe a smooth complex projective variety such that the Albanese map of Xis generically ¿nite onto its image. Here we study the so-called eventual m-paracanonical map of X, whose existence is implied by the results of ... -
The representation problem of pairs of symmetric second order tensors in the context of solid mechanics
Barja Yáñez, Miguel Ángel; Carol, Ignacio; Planas Vilanova, Francesc d'Assís; Rizzi, Egidio (2003)
Report de recerca
Accés restringit per decisió de l'autor -
The structure and slope of bielliptic fibrations
Barja Yáñez, Miguel Ángel (1997)
Article
Accés obert -
TOPOLOGIA
Barja Yáñez, Miguel Ángel (Universitat Politècnica de Catalunya, 2014-06-03)
Examen
Accés restringit a la comunitat UPC -
TOPOLOGIA (Examen 2n quadrim)
Barja Yáñez, Miguel Ángel (Universitat Politècnica de Catalunya, 2005-04-05)
Examen
Accés restringit a la comunitat UPC -
Topologia. Apunts
Barja Yáñez, Miguel Ángel; Pascual Gainza, Pere; Roig Martí, Agustín; Carreras, Judit; Amorós Torrent, Jaume (Universitat Politècnica de Catalunya, 1998)
Apunts
Accés obert -
Xiao's conjecture for general fibred surfaces
Barja Yáñez, Miguel Ángel; González Alonso, Víctor; Naranjo del Val, Joan Carles (2018-06-01)
Article
Accés obertWe prove that the genus g, the relative irregularity qf and the Clifford index cf of a non-isotrivial fibration f satisfy the inequality qf=g-cf. This gives in particular a proof of Xiao’s conjecture for fibrations whose ... -
Xiao's conjuecture for general fibred surfaces
Barja Yáñez, Miguel Ángel; González Alonso, Víctor; Naranjo del Val, Joan Carles (2014-01-10)
Report de recerca
Accés obertWe prove that the genus g, the relative irregularity q_f and the Clifford index c_f of a non-isotrivial fibration f satisfy the inequality q_f=g-c_f. This gives in particular a proof of Xiao’s conjecture for fibrations ...