| Links' Seminars and Public Events |   |
| 2016 | |
|---|---|
Fri 18th Nov all day | Florent Capelli visit |
Tue 8th Nov 2:30 pm 4:30 pm | Seminar Link by Helmut Seidl: "Equivalence of Deterministic Top-Down Tree-to-String Transducers is Decidable" Abstract: We show that equivalence of deterministic top-down tree-to-string transducers is decidable, thus solving a long standing open problem in formal language theory. We also present efficient algorithms for subclasses: polynomial time for total transducers with unary output alphabet (over a given top-down regular domain language), and co-randomized polynomial time for linear transducers, these results are obtained using techniques from multi-linear algebra. For our main result, we prove that equivalence can be certified by means of inductive invariants using polynomial ideals. This allows us to construct two semi-algorithms, one searching for a proof of equivalence, one for a witness of non-equivalence. "Lille-Salle B31 " |
Mon 7th Nov 2:00 pm 4:00 pm | PhD defense Adrien Boiret |
Fri 4th Nov all day | colis general meeting  Paris |
Thu 27th Oct 10:00 am 6:00 pm | Links day |
Thu 27th Oct all day | links day |
Thu 20th Oct 2:00 pm 4:00 pm | Seminar Links by Vincent Hugot: "Top-Down Transducers for Data Trees" Abstract: Tree transducers have a wide range of application domains ranging from compiler construction, program analysis, and computational linguistics, to semi-structured databases and file system transformations. A common application of these domains is to specify and verify transformations of data trees, i.e., trees whose nodes are labeled by data values from an infinite domain. Most existing classes of tree transducers and their formal studies, however, are restricted to trees over finite signatures without data. In this paper, we lift the most prominent class of top-down tree transducers to data trees, such that its good properties are preserved. In particular, we show that top-down transducers for data trees have a decidable equivalence problem, without imposing any linearity restriction as in previous approaches based on symbolic top-down tree transducers. "Lille-Salle B21" |
Thu 13th Oct 2:00 pm 5:30 pm | comité de projet |
Thu 13th Oct 2:00 pm 3:00 pm | Seminar Christof Löding "Lille-Salle B21" |
Thu 13th Oct to Fri 14th Oct all day | visit christof löding |
