Section: Highlights of the Year
Highlights of the Year
Certain Query Answering as Access Control
P. Bourhis  presented at LICS — the top conference in logic in computer science — a general framework for querying databases with visible and invisible relations. This work was done in cooperation with Oxford, Santa Cruez, and Bordeaux. It generalizes in a uniform manner the problems of certain query answering and access control for relational databases. Invisible relations are subject to the open world assumption possibly under constraints, while visible relations are subject to the closed world assumption. Bourhis then shows that the problem of answering Boolean conjunctive queries in this framework is decidable, and studies the complexity of various versions of this problem. It turns out that the complexity increases compared to the problem of certain query answering, given that the closed world assumption is adopted for the added visible relations.
Five ANR Projects
Two new ANR projects were accepted this year: Delta and Headwork. This makes Links a partner of 5 ANR projects in 2016.
PhD Defense of A. Boiret
The defense of the PhD thesis of A. Boiret  on "Normalization and Learning of Transducers on Trees and Words" under the supervision of J. Niehren and A. Lemay was highly appreciated by the reviewers. In particular, he illustrated very clearly how to learn top-down tree transformations subject to regular schema restriction , , . Furthermore, he solve a problem open for more than 20 years on how to learn rational functions, i.e. word transducers with regular lookahead.