THeory and Evidence to Measure Influence in Social structures

Joint PRC with LAMSADE (PI) and LIP6.

The THEMIS project aims at producing a general ordinal theory of cooperative interaction situations and power indices for the formulation of a portfolio of social ranking solutions applied to different domains of artificial intelligence, such as decision theory, game theory, computational social choice and multi-agent systems. In particular, the project will focus on the following families of problems: 1) the axiomatic design of novel social ranking solutions accompanied with a road-map of principles guiding users to the most adapted scenario; 2) the impact of the computational difficulties of algorithms for social ranking and their vulnerability to strategic behaviour; 3) the dynamics of coalition formation and the effect of social ranking solutions on the behaviour of individuals to form stable coalition structures; 4) the application of compact preference representation to efficiently compute social ranking solutions and to assess their robustness to changes and to manipulations. Each family of problems from (1) to (4) is studied in a specific work package, and a fifth work package is devoted to the implementation and to the application of our models and solutions to case-studies from voting theory, the analysis of influence measures on social networks, argumentation theory and multi-criteria decision analysis. Specific examples of application will concern the ranking of European countries according to their effective impact over EU public policies; the interpretation of weights for the electoral college of members of the Paris Sciences et Lettre (PSL) University; the comparison of influence, popularity, trends, etc., over Twitter and other social networks; the definition of gradual semantics to rank arguments with regard to their overall strengths in a debate; the representation of positive and negative synergies between criteria in a multi-criteria decision analysis problem.