Which graphical models are difficult to learn?

We consider the problem of learning the structure of Ising models (pairwise binary Markov random fields) from i.i.d. samples. While several methods have been proposed to accomplish this task, their relative merits and limitations remain somewhat obscure. By analyzing a number of concrete examples, we show that low-complexity algorithms systematically fail when the Markov random field develops long-range correlations. More precisely, this phenomenon appears to be related to the Ising model phase transition (although it does not coincide with it)

A Family of Tractable Graph Distances

Important data mining problems such as nearest-neighbor search and clustering admit theoretical guarantees when restricted to objects embedded in a metric space. Graphs are ubiquitous, and clustering and classification over graphs arise in diverse areas, including, e.g., image processing and social networks. Unfortunately, popular distance scores used in these applications, that scale over large graphs, are not metrics and thus come with no guarantees. Classic graph distances such as, e.g., the chemical and the CKS distance are arguably natural and intuitive, and are indeed also metrics, but they are intractable: as such, their computation does not scale to large graphs. We define a broad family of graph distances, that includes both the chemical and the CKS distance, and prove that these are all metrics. Crucially, we show that our family includes metrics that are tractable. Moreover, we extend these distances by incorporating auxiliary node attributes, which is important in practice, while maintaining both the metric property and tractability.Comment: Extended version of paper appearing in SDM 201

The organising principles of the society of Jesus - from the pastorate to governmentality

Foucault’s concepts of Pastoral power and “governmentality” have led to the development of the London school of “governmentalists” (McKinlay and Pezet 2010). However, extant literature on governmentality drawn from this school of thought has undertaken an analytics of power centred on the deployment of governmental forms of power at the State level, not taking into consideration another entity that emerged after modernity, the modern enterprise, and not going beyond the 19th century, thereby trapping “governmentality” studies inside their own modern discourse. Following Foucault’s established relation between Pastoral power and “governmentality”, this thesis analyses the form of organising deployed by an organisation that emerged in the 16th century, apparently being able to survive into modernity without adopting modern managerial business categories. This organisation is the Society of Jesus, commonly known as the Jesuits. The first part of this thesis will analyse the relevance of the Society of Jesus for organisational studies and will show how modern business categories fail to explain its structural resilience. The second part of the thesis introduces Pastoral power as a possible explanation for the apparent structural resilience of the Society of Jesus. Following this line of reasoning, and after having established an analytics of power as a possible methodological framework, the Society of Jesus’ “organising practices” will be presented, leading to the conclusion that this entity, having emerged at the cornerstone of modernity, deployed practices that represent a significant shift when compared with previous Pastoral forms of organising. The fact that the Society of Jesus clearly intended to deploy practices for the conduction of geographicallydispersed individuals leads to the conclusion that it deployed a “protogovernmental” form of power, and that the rationality underpinning its practices, although not entirely modern, is clearly at the cornerstone of modernity and can therefore be enlightening to an understanding of how modern managerial categories might have emerged

Oral-aural accounting and the management of the Jesuit corpus

The roles of written and visual accounting techniques in establishing conditions of possibility in modern management decision making are well documented. In contrast, this paper looks beyond the “grammatocentric”, and analyzes a practice of oral accounting – the Account of Conscience – that began in the Society of Jesus in the sixteenth century, and has persisted largely unchanged to the present day. In this practice, we see historically relevant pastoral practices evolving into techniques of government that begin to resemble modern governmentality. The paper compels a more general consideration of oral–aural practices and their role in constructing relationships of authority and accountability