Stickelberger's congruences for absolute norms of relative discriminants

We give an improvement of a result of J. Martinet on Stickelberger's congruences for the absolute norms of relative discriminants of number fields, by using classical arguments of class field theory

No Riemann-hurwitz formula for the p-ranks of relative class groups

We disprove, by means of numerical examples, the existence of a Riemann-Hurwitz formula for the p-ranks of relative class groups in a p-ramified p-extension K/k of number fields of CM-type containing ?\_p. In the cyclic case of degree p, under some assumptions on the p-class group of k, we prove some properties of the Galois structure of the p-class group of K; but we have found, through numerical experimentation, that some theoretical group structures do not exist in this particular situation, and we justify this fact. Then we show, in this context, that Kida's formula on lambda invariants is valid for the p-ranks if and only if the p-class group of K is reduced to the group of ambiguous classes, which is of course not always the case.Comment: 6 pages + tables num\'erique

I\u27ll Rise : Rememory, Hope and the Creation of a New Public Sphere In Ben Harper\u27s Music

Recent studies about resistance music in the United States primarily focus on the hip-hop movement. However, it does not offer the only musical discourse contesting contemporary injustices. Even though the debate about hip-hop is a crucial one that deserves full attention, it seems necessary to widen the current conversation on music to take into account a wider array of musical genres and artists. This will in turn allow us to see the revolutionary power of music in its full force. In the United States, black music, from the Spirituals to Rhythm and Blues, has undeniably been a potent agent for social change. Because they enable strangers to identify with each other through a common discourse, songs from many different genres have fostered what Benedict Anderson calls imagined communities

Transatlantic Literary Networks during the Cold War: Emir Rodríguez Monegal, Reader for Gallimard

In this paper, I propose to address the issue of transatlantic networks and the circulation of literary paradigms between Latin America and Europe. I will focus on a relevant actor from the time of the well-known and still controversial “boom” of Latin American narrative, within the context of the Cold War (Franco 2002, Sorensen 2007, Alburquerque 2010). This was a key moment in the internationalization of Latin American writers, as José Donoso underlined in Historia personal del ‘boom’ (1972, 1983). Donoso highlighted some names that served as nodes, such as Carlos Fuentes, who played an important role, thanks to his extraordinary and natural handling of informal networks (Gras 2015). Among these names that had a specific weight in the process of international recognition of the “boom”, Donoso also highlights the figure of the Uruguayan critic Emir Rodríguez Monegal (1921–1985), to whom I will devote these pages.  I will present a very specific—and even anecdotal—example: the reading reports that Rodríguez Monegal wrote for the prestigious French publishing house Gallimard over a single year, 1967. I will also analyze the relative influence of a recognized critic in the configuration of a publisher’s catalog. This exemplifies his ability to direct, in some way, the attention of the French public to a handful of Latin American writers, based on his suggestions and proposals for translation. In doing this, I also contribute to an understanding of the decision-making mechanisms of a publisher of the magnitude of Gallimard, which led to undertaking (or not) an expensive and risky translation process

Analysis of the classical cyclotomic approach to fermat's last theorem

We give again the proof of several classical results concerning the cyclotomic approach to Fermat's last theorem using exclusively class field theory (essentially the reflection theorems), without any calculations. The fact that this is possible suggests a part of the logical inefficiency of the historical investigations. We analyze the significance of the numerous computations of the literature, to show how they are probably too local to get any proof of the theorem. However we use the derivation method of Eichler as a prerequisite for our purpose, a method which is also local but more effective. Then we propose some modest ways of study in a more diophantine context using radicals; this point of view would require further nonalgebraic investigations.Comment: Publications Math\'ematiques UFR Sciences Techniques Besan\c{c}on 2010 (2010) 85-11

Intention recognition for gaze controlled robotic minimally invasive laser ablation

Eye tracking technology has shown promising results for allowing hands-free control of robotically-mounted cameras and tools. However existing systems present only limited capabilities in allowing the full range of camera motions in a safe, intuitive manner. This paper introduces a framework for the recognition of surgeon intention, allowing activation and control of the camera through natural gaze behaviour. The system is resistant to noise such as blinking, while allowing the surgeon to look away safely at any time. Furthermore, this paper presents a novel approach to control the translation of the camera along its optical axis using a combination of eye tracking and stereo reconstruction. Combining eye tracking and stereo reconstruction allows the system to determine which point in 3D space the user is fixating, enabling a translation of the camera to achieve the optimal viewing distance. In addition, the eye tracking information is used to perform automatic laser targeting for laser ablation. The desired target point of the laser, mounted on a separate robotic arm, is determined with the eye tracking thus removing the need to manually adjust the laser's target point before starting each new ablation. The calibration methodology used to obtain millimetre precision for the laser targeting without the aid of visual servoing is described. Finally, a user study validating the system is presented, showing clear improvement with median task times under half of those of a manually controlled robotic system