Rendiconti dell'Istituto di Matematica dell'Università di Trieste: an International Journal of Mathematics vol.46 (2014)

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Editorial policy The journal Rendiconti dell’Istituto di Matematica dell’università di Trieste publishes original articles in all areas of mathematics. Special regard is given to research papers, but attractive expository papers may also be considered for publication. The journal usually appears in one issue per year. Additional issues may however be published. In particular, the Managing Editors may consider the publication of supplementary volumes related to some special events, like conferences, workshops, and advanced schools. All submitted papers will be refereed. Manuscripts are accepted for review with the understanding that the work has not been published before and is not under consideration for publication elsewhere. Our journal can be obtained by exchange agreements with other similar journals.

Instructions for Authors Authors are invited to submit their papers by e-mail directly to one of the Managing Editors in PDF format. All the correspondence regarding the submission and the editorial process of the paper are done by e-mail. Papers have to be written in one of the following languages: English, French, German, or Italian. Abstracts should not exceed ten printed lines, except for papers written in French, German, or Italian, for which an extended English summary is required. After acceptance, manuscripts have to be prepared in LaTeX using the style rendiconti.cls which can be downloaded from the web page. Any figure should be recorded in a single PDF, PS (PostScript), or EPS (Encapsulated PostScript) file.

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Recent Submissions

Now showing 1 - 5 of 15
  • Publication
    On quotient orbifolds of hyperbolic 3-manifolds of genus two
    (2014-12-23)
    Bruno, Annalisa
    ;
    Mecchia, Mattia
    We analyse the orbifolds that can be obtained as quotients of genus two hyperbolic 3-manifolds by their orientation preserving isometry groups. The genus two hyperbolic 3-manifolds are exactly the hyperbolic2-fold branched coverings of 3-bridge links. If the3-bridge link is a knot, we prove that the underlying topological space of the quotient orbifold is either the 3-sphere or a lens space and we describe the combinatorial setting of the singular set for each possible isometry group. In the case of 3-bridge links with two or three components, the situation is more complicated and we show that the underlying topological space is the3-sphere, a lens space or a prism manifold. Finally we present an infnite family of hyperbolic 3-manifolds that are simultaneously the 2-foldbranched covering of three inequivalent knots, two with bridge number three and the third one with bridge number strictly greater than three.
      581  490
  • Publication
    Non resonance conditions for radial solutions of non linear Neumann elliptic problems on annuli
    (2014-12-23)
    Sfecci, Andrea
    An existence result to some nonlinear Neumann elliptic problems defined on balls has been provided recently by the author in [21]. We investigate, in this paper, the possibility of extending such a result to annuli.
      639  448
  • Publication
    On Grothendieck's counterexample to the Generalized Hodge Conjecture
    (2014-12-23)
    Portelli, Dario
    For a smooth complex projective variety X, let $N^p$ and $F^p$ denote respectively the coniveau filtration on $H^i(X,Q)$ and the Hodge filtration on $H^i(X,C).$ Hodge proved that $N^p H^i(X,Q )\subset F^p H^i(X,C )\cap H^i(X,Q ),$ and conjectured that equality holds. Grothendieck exhibited a threefold X for which the dimensions of $N^{1}H^{3}(X,Q )$ and $F^{1} H^{3}(X,C )\cap H^{3}(X,Q )$ differ by one. Recently the point of view of Hodge was somewhat refined (Portelli, 2014), and we aimed to use this refinement to revisit Grothendieck's example. We explicitly compute the classes in this second space which are not in $N^{1}H^{3}(X,Q ).$ We also get a complete clarification that the representation of the homology customarily used for complex tori does not allow to apply the methods of (Portelli, 2014) to give a different proof of $N^{1} H^{3}(X,Q )\subsetneq F^{1} H^{3}(X,C )\cap H^{3}(X,Q ).$
      859  439
  • Publication
    On an inequality from Information Theory
    (2014-12-23)
    Horst, Alzer
    We prove that the inequalities $$ \sum_{j=1}^n \frac{q_j (q_j-p_j)^2}{q_j^2 +m_j^{\alpha} M_j^{1-\alpha}} \leq \sum_{j=1}^n p_j \log \frac{p_j}{q_j} \leq \sum_{j=1}^n \frac{q_j (q_j-p_j)^2}{q_j^2 +m_j^{\beta} M_j^{1-\beta}} \quad{(\alpha, \beta \in \mathbb{R})}, $$ where $$ m_j=\min(p_j^2, q_j^2) \quad\mbox{and} \quad{M_j=\max(p_j^2, q_j^2)} \quad(j=1,...,n), $$ hold for all positive real numbers $p_j, q_j$ $(j=1,...,n; n\geq 2)$ with $\sum_{j=1}^n p_j=\sum_{j=1}^n q_j$ if and only if $\alpha\leq 1/3$ and $\beta\geq 2/3$. This refines a result of Halliwell and Mercer, who showed that the inequalities are valid with $\alpha=0$ and $\beta=1$.
      609  438
  • Publication
    Resolution of the ideal sheaf of a generic union of conics in P3:I
    (2014-12-23)
    Rahavandrainy, Olivier
    We work over an algebraically closed field K of characteristic zero. Let Y be the generic union of $r \geq 2$ skew conics in $P^3_K$, $I_Y$ its ideal sheaf and v the least integer such that $h^0(I_Y(v)) > 0$. We first establish a conjecture (concerning a maximal rank problem) which allows to compute, by a standard method, the minimal free resolution of $I_Y$ if $r\geq 5$ and $\displaystyle{\frac{v(v+2)(v+3)}{12v+2}
      672  466