On the exceptional locus of the birational projections of normal surface singularity into a plane

Given a normal surface singularity $(X, Q)$ and a birational morphism to a non- singular surface $\pi : X \to S$, we investigate the local geometry of the exceptional divisor $L$ of $\pi$. We prove that the dimension of the tangent space to $L$ at $Q$ equals the number of exceptional components meeting at $Q$. Consequences relative to the existence of such birational projections contracting a prescribed number of irreducible curves are deduced. A new characterization of minimal singularities is obtained in these terms.Comment: 12 pages, 2 figure

Geometry of the Kimura 3-parameter model

The Kimura 3-parameter model on a tree of n leaves is one of the most used in phylogenetics. The affine algebraic variety W associated to it is a toric variety. We study its geometry and we prove that it is isomorphic to a geometric quotient of the affine space by a finite group acting on it. As a consequence, we are able to study the singularities of W and prove that the biologically meaningful points are smooth points. Then we give an algorithm for constructing a set of minimal generators of the localized ideal at these points, for an arbitrary number of leaves n. This leads to a major improvement of phylogenetic reconstruction methods based on algebraic geometry.Comment: 26 pages with 4 figure

A syntactic-semantic analysis of English (non)-dativizable constructions in the production of a set of 2L1 English/Spanish simultaneous bilingual twins

This paper analyzes the syntactico-semantic factors which trigger Dative shift in English dativizable verbs, i.e. those verbs that allow alternation between double object and prepositional complement constructions. It also focuses on non-dativizable verbs that restrict their subcategorization framework to either double object or prepositional complement constructions. This syntactico-semantic relation between dativizable and nondativizable structures is addressed in acquisition by examining the incidence for the two verb types in a set of English/Spanish 2L1 bilingual twins. Our results show that the syntactic and semantic features that dativizable and non-dativizables present go hand in hand with the age of first occurrence and the language development of the participants. Hence, dativizable to-dative double object constructions (DOC) are the utterances produced the earliest at the age of 2, as opposed to dativizable to/for-datives and non-dativizable constructions, which begin to emerge at around the age of 3. Finally, our results also suggest that the high adult input frequency explains the twins' early production of dativizable structures and that, in the same way, the children's low exposure to non-dativizable utterances correlates with the later occurrence in the twins' spontaneous production.peer-reviewe

Equisingularity classes of birational projections of normal singularities to a plane

Given a birational normal extension S of a two-dimensional local regular ring R, we describe all the equisingularity types of the complete ideals J in R whose blowing-up has some point at which the local ring is analytically isomorphic to S. The problem of classifying the germs of such normal surface singularities was already posed by Spivakovsky (Ann. of Math. 1990). This problem has two parts: discrete and continous. The continous part is to some extent equivalent to the problem of the moduli of plane curve singularities, while the main result of this paper solves completely the discrete part.Comment: 22 pages, 3 figures. To appear in Advances in Mathematic

Las clausulas de tregua sindical en el sistema italiano de relaciones laborales

The peace obligation in Italy was widely discussed in the doctrine in the 50’s. However, the interest for this argument died in that period without a particular solution. Since then, neither the doctrine nor the legislator have been dedicated to study the peace obligation until it appeared the famous “Fiat case”. This case has opened the discussion about the existence and binding force of the trade union truce agreement.El tema de las cláusulas de tregua sindical en Italia fue ampliamente debatido en la doctrina en los años 50, argumento cuyo interés se extinguió en aquel periodo sin haber llegado a una concreta solucion. Desde entonces, ni la doctrina ni tampoco el legislador se habían ocupado del pacto de tregua hasta que apareció el conocido “caso Fiat”, por el cual se ha vuelto a discutir sobre la existencia y la fuerza vinculante del pacto de tregua sindical

TWILIGHT OF THE TOFFS: FALL OF A CASTE, RISE OF A MYTH

Dissertation ABSTRACT: This dissertation deals with the representation of the interwar upper classes (above all, the aristocracy) in the contemporary English novel. I have chosen three novels for my study: Ian McEwan‟s Atonement (2001), Kazuo Ishiguro‟s The Remains of the Day (1989) and Evelyn Waugh‟s Brideshead Revisited (1945). My main critical perspective is a structuralist one, namely that of Roland Barthes in his Mythologies (1956). I show how, notwithstanding the period in which they were written, their aesthetic orientation, or their authors‟ personal stand concerning their society, the chosen novels, spanning six decades, can be analyzed by applying the same „figures of myth‟, according to Barthes‟s terminology. To facilitate a better understanding of this literature, I have also connected it with a common historical and ideological background, that of the interwar period. Moreover, as Barthes‟s ideological stand is a Marxist one, if heterodoxically so, I will be relating the novels to a number of Marxist concepts, such as hegemony, dominant and residual cultures, or false consciousness. Concepts from other fields of contemporary intellectual history, such as psychoanalysis, will also be featured for the same purpose. Finally, I have also given a prominent role to social history in my analysis. My main conclusion will be that myth has superseded factual representation of the traditional landed aristocracy, turning it into a category that is still operative in the domain of fiction, informing the international reading public‟s views of British society and culture, even after the historical demise of that social class