Nash consistent representation of effectivity functions through lottery models

Effectivity functions for finitely many players and alternatives are considered. It is shown that every monotonic and superadditive effectivity function can be augmented with equalchance lotteries to a finite lottery model---i.e., an effectivity function that preserves the original effectivity in terms of supports of lotteries---which has a Nash consistentrepresentation. In other words, there exists a finite game form which represents the lottery model and which has a Nash equilibrium for any profile of utility functions, where lotteriesare evaluated by their expected utility. No additional condition on the original effectivity function is needed.microeconomics ;

A Stability Index for Local Effectivity Functions

We study the structure of unstable local effectivity functions defined for n players and p alternatives. A stability index based on the notion of cycle is introduced. In the particular case of simple games, the stability index is closely related to the Nakamura Number. In general it may be any integer between 2 and p. We prove that the stability index for maximal effectivity functions and for maximal local effectivity functions is either 2 or 3.Effectivity function, local effectivity function, acyclicity, stability index, Nakamura Number, acyclicity.

A Stability Index for Local Effectivity Functions

We study the structure of unstable local effectivity functions defined for n players and p alternatives. A stability index based on the notion of cycle is introduced. In the particular case of simple games, the stability index is closely related to the Nakamura Number. In general it may be any integer between 2 and p. We prove that the stability index for maximal effectivity functions and for maximal local effectivity functions is either 2 or 3.Stability index; acyclicity; strong Nash Equilibrium; core, solvability; consistency; simple game; effectivity function

Screen theory and film culture, 1977-1987.

My work in the 1970s and 1980s was developed with the evolving body of work now loosely called 'c e theory'. It centred on notions of authorship, spectatorship and art cinema with specific reference to the films of Carl Dreyer. In my research and writing on Dreyer's film Vampyr I applied the literary concept of the fantastigue to cinema, one of the first substantial theoretical contributions to a now established area of publication and research. According to one writer' this work was "probably the most ambitious attempt to apply Todorov's approach to cinema", a "notable exception" in the theoretical writing of that time. This was part of the wider movement associated with SEFT and Screen to interrogate the uncritical realism which dominated 1970s film studies. In my subsequent writing on Dreyer I explored a structuralist but more psychoanalytically informed discussion of genre, developing the concept of the "Dreyer text" as a way of bringing psychoanalytic concepts to compliment and complicate structuralist notions of authorship and genre. I was part of a loose group at Screen which was passionate both about cinema and ideas. While polemically defending the new concepts we were bringing to bear on cinema, we were equally concerned with their institutional placing. Our work concentrated both on regimes of looking allowed to the spectator by texts and their institutional placing. We focussed on political and discursive structures of the cinematic institution and developed a concept of `cinema as social practice'. In particular I pushed for a cultural critique of British Independent cinema and its institutions, which was continued in my work on screen acting. I was also instrumental in extending Screen theory to other visual arts. I felt that the sometime parochialism of film studies lay in part in its separation from analysis of other forms of visual culture. In my full context statement I wish to explore limitations in the political, semiotic and psychoanalytic models which I (as did many others) adopted at the time. What I now see as Screen theory's 'blind spots' in relation to issues of sexual orientation and race can be traced back to the problematic of this period. My own subsequent research on gay and lesbian cinema as well as film and television projects on screen acting (Acting Tapes) psychoanalysis (Between Two Worlds) and Frantz Fanon (Frantz Fanon: Black Skin White Mask) came out of dissatisfaction with that earlier project as it was then conceived. The form chosen - the essay and review - reflects the difficulty of thinking through these issues. [James Donald (ed), 'Fantasy and the Cinema', British Film Institute, London 1989] In essence my proposal involves looking back at my work around Dreyer and what one could broadly call my `film culture' work, and arguing that what was sometimes felt and described as a theory: practice division between these two domains could be more usefully thought of in retrospect in terms of two overlapping modes of theoretical production involving different notions of institution, conjuncture, subject etc. In looking again at the strengths and weaknesses of the work I am submitting here, however, I still expect key terms of subject and history, discourse and institution, to remain in place, modified and nuanced by the substantial range of work in psychoanalysis, cultural studies and queer theory that Screen in part engendered and which my work participated in

DIFFRACTING REPRESENTATION: TOWARDS A SITUATED AESTHETICS OF TECHNOSPACES

Thesis embargoed until 01-09-2017. Embargo set on 04/08/2015 by CLC, Graduate School.My research for this thesis focusses on the concepts of representation and space in order to demonstrate their theoretical and practical co-implications. Discussing various theorists of space in the first part and analyzing a number of artists and artworks as case studies in the second part, I elaborate a critique of the representational imaginary in order to articulate an alternative notion of representation by means of which a relational, qualitative and performative spatiality can emerge. I specifically focus on technospaces, which I consider a privileged field for observing the intersections of representation and spatiality; it is a field in which the use of spatial metaphors abounds, very often relying on a series of dichotomies (such as location and mobility, the real and the virtual) that have employed and, in most cases, reinforced the traditional idiom of representational. Drawing on the lessons of feminist theory, particularly on approaches to the politics of location, from Adrienne Rich‘s initial formulation to the situated knowledge theorized by Donna Haraway, I elaborate a situated aesthetics of technospaces in which the observer‘s engagement with representational practices replaces the view from a distance of traditional representation, so that her/his position is accounted for together with the history of the production of space and its multiple representations. For this reason, I also formulate an articulatory turn in representation based on Haraway‘s semiotics in order to propose a non-reflexive notion of representation in which invention and factuality eventually meet

Decision-making strategies in the general practice

With regard to the question what is to be tran$mitted in teaching two aspects have to be considered: a) the contents of the specialty; and b) the problem-solving methods with regard to the specialty. On the first aspect an overwhelming amoUnt of book$ and articles has bee~ written in medicine. The second 8Spect is usually only mentioned in passing. In my opinion, ~his subject has thusfar been greatly undervalued. When one is unable to trace the - problem-solving processes how can anyone determine the efficscy, the effectivity, and the efficiency of this process, or value~ the outcome. To state it in Magerien terms: "If you do not know where to g;o, you may very well end up somewhere else- and not even know it." How physicians solve clinical problems is the main object of this research. The investigator studied and modeled two of the eldest and famous ways of pJroblei!Jlrsolving: the deductive and the inductive strategy9 with the modern probability reasoning viewed as an extension of the latter strategy. All 68 physicians who participated in this investigation used the inductive strategy for the -usually four - presented patient-problems. Within the inductive strategy three variants could be distinguished. The consequences of this finding are far-reaching. As the inductive strategy does not include a logical hierarchy of argumentationsteps, retracing of the process is impossible. (This aspect is also relate~ to our opinions about experience-knowledge end teaching)A As the hypothesis generation is prior to the acquisition of infot~tion, this latter aspect can only be viewed in the light of the former~ and thus limited to a small number of domains. As the hypothesis generation is - partly - unrelated to the total available amount of information, the decision making (chopsing the ultimate diagnostic hypothesis) will usually follow implicit~ personal trends and standards, e.g. satisfying minimal eicpectations (Satisficing Theory, Simon} or risk-avoiding prospects (Prospect Theory, Kahnemann & Tversky). It suggests a highly personal character of diagnostics and/or the therapeutic management, which is contradictory to general accessibility of medical knowledge and medical teaching. This feature of personal concepts easily links up with Polanyi's theory of "PeJrsonal" or 91Tacit Knowledge" as contrasted to "Objective Knowledge" (Popper) 9 which has general accessibility and validity. During the investigation this as~oct came forth. The framework of the investigation (patient simulation) end the special definitions and coding of illness elements (symptoms, signs9 tests) all~wed for comparing similar conceptions (diagnoses, treatments) ~ong the participants. These comparisons confirm Polanyi's theory and the concepts of inductive reasoning. Mutual comparibility of diagnoses seems hardly possible when analysing these conceptions into their basic elements (symptoms etc.). This aspect touches upon one of the main cornerstones of clinical ~edicine. When the starting positions have not been unequivocally defined treatment, .,;ie-Jed as the intervention in the natural course of a disease, can only lead t4:!1 uncertain outcomes. The lack of · standardized :medical definitions and a tmiform, unambiguous taxonomy inhibits the application of a formalised, normative decision theorry for clinical medicine. Future planning aims at a reconsideration of medical terminology~ medical taxonomy and medical problem-solving methods by means of clustering the basic elements of clinical medicine