Section: New Results
Tree Structured Presentation of Symbolic Temporal Data
Participants : Florent Jacquemard, Michael Rusinowitch [Project-team Cassis] , Luc Segoufin [Project-team Dahu] .
In traditional music notation, in particular in the languages used for the notation of mixed music such as Antescofo DSL, the durations are not expressed by numerical quantities but by symbols representing successive subdivisions of a reference time value (the beat). For this reason, trees data structures are commonly used for the symbolic representation of rhythms in computer aided composition softwares such as OpenMusic (developed at Ircam). It is therefore worth studying the applications in rhythm notation of existing formalisms for recognizing, querying, transforming and learning sets of tree structured data.
In 2012 we have studied several classes of tree recognizers which could be of interest in this context. First, with Michael Rusinowitch we have proposed in  a novel class of automata computing on unranked trees, which are context free in two dimensions: in the the sequence of successors of a node and also along paths. Second, we studied with Luc Segoufin  automata and logics computing on data trees and their relationship. Data trees are unranked ordered trees where each node carries a label from a finite alphabet and a datum from some infinite domain.