Editors: Laurent Beauguitte ; Claire Lagesse ; Marion Maisonobe

The strength of vulnerable positions: Financial hegemony and disruptive potential

Fabien Foureault.
This article addresses the structural power of banks by analyzing the market for Leveraged Buy-Outs (LBOs) in France during the 2000s. It attempts to operationalize the concept of financial hegemony in an original way, working from the idea of point-vulnerability in a graph, introducing a method that can be used to model a network according to this criteria (cohesive blocking). The analysis shows that banks oc-cupy not only the most central, but also the most vulnerable positions in the system compared with corporations and private equity firms. The crisis of 2007-2008 has enabled banks to impose their conditions and to firmly reinstate their hegemony which was somewhat contested during the bubble period. The structure that results from such an evo-lution has ambiguous implications for systemic risk.

A Precursor of Digital Humanities ? The First Automated Analysis of an Ancient Economic Network (Gardin & Garelli, 1961). Implementation, Theorization, Reception

Sébastien Plutniak.
From as early as the 1950s, J.C. Gardin's work spanned both archaeology and the emerging automation of numerical computation and documentation. In 1961, with P. Garelli, he published the first automated application of graph theory to historical materials, working from Assyrian cuneiform tablets documenting economic relations. This work was then widely ignored both in archeology and network analysis. However, in the past twenty years, socio-epistemic claims related to the growth of the Internet and computing (digital humanities, computational archaeology, etc.) have brought a surge of interest in Gardin's work, which is now regarded as pioneering. Working from archive materials and publications, this paper shows how a historical sociology of scientific writings can be relevant to the history of automation in historical sciences. The paper examines Gardin's recognition as an influential forerunner of computational archeology, showing that : 1) although Gardin had access to resources (financial, instrumental, etc.) that were rare at the time, and could have provided material for the foundation of a school or a specialty, he did not however pursue this ambition; 2) the demonstrative purposes pursued by Gardin with his study of 1961 economic networks varied between the 1960s (demonstrating the relevance of non-numerical computation) and the 1980s (legitimizing simulation in the social sciences), but were never concerned with network analysis as such.

Constellations of kinship in the medieval nobility of Île-de-France (1000-1440)

Laurent Nabias.
This article provides a detailed description of the network of alliances and the matrimonial constellations established from 1000 to 1440 between noble “topolineages” of the upper, middle and low nobility in the Île-de-France (Paris region), with the aim of understanding their marital strategies. For these topolineages, the aim was to ensure the reproduction of aristocratic domination in a context where new actors emerged, including recently ennobled individuals who were aggregated to the existing nobility. Using the Puck software, the author carries out a systematic exploration of alliances and realliances formed through affinity and inbreeding in order to identify the role played by kinship in solidarities. Datasets stored on the Kinsource platform are used to build dated graphs of these networks, highlighting alliances and consanguineous marriages. The development of network patterns makes it possible to identify expansions of matrimonial components, as well as the interruption of their expansion around 1290. Computer analysis shows that aristocrats looked for their spouses within authorized boundaries, and did not hesitate to reproduce past unions between the same lineages as long as the generational gap between the common ancestors and the spouses complied with canonical laws.

Journey in cluster: What about its relational promise ?

Estelle Vallier.
This article focuses on inter­-organizational and interpersonal networks within a biocluster (a geographical pool of biotechnology companies, laboratories and universities). Diverse forms of interactions and interpenetration can be observed across the three spheres of science, industry and education. Using network analysis and the traditional methods of sociology (observations, interviews and surveys), this article reveals that while there are limited formal relations between organizations, phenomena of mutual acquaintance can be observed on an inter­individual level. At employee level, these acquaintances manifest themselves through a shared sense of belonging to the "small world of genomics", and through the sharing of experience in case of problems. Within teams, there are collegial and sometimes even friendly relations, but they rarely turn into professional interaction. In this context, individuals may activate their interpersonal networks for the purposes of occupational mobility, giving rise to an internal labor market. However, this market is disconnected from local students, although the university works to adapt its curriculum to the needs of local companies and laboratories.