4th Int. Workshop on Trends in Tree Automata and Tree Transducers (TTATT 2016)

Tree automata and tree transducers have recently received increased attention due to their applications in verification, natural language processing, and XML. The workshop provides an opportunity for researchers and practitioners from the different areas to discuss recent developments and ideas. The workshop also welcomes participants working on string automata and string transducers.

The workshop proceedings are available. Thank you for making TTATT 2016 a success.

• We mourn the untimely loss of Zoltán Ésik (University of Szeged, Hungary). His contributions will be remembered. RIP.
• Kenji Hashimoto (Nagoya University, Japan): Determinacy and Query Preservation of Tree Transducers
  Determinacy and query preservation have been studied as formalizations of information preservation in data transformation in the database community. A transformation (or view) determines a query if there is a function that can map the output of the view to the output of query. Also, a view preserves a query in a designated class if the view determines the query with a function in the same class as the given query. We study the problems of deciding for a given view and query on trees, whether the view determines/preserves the query. In the talk, I present our results concerning the decidability and complexity on determinacy and query preservation for views given by functional linear extended bottom-up tree transducers and queries given by functional bottom-up tree transducers. I also present another result on query preservation when queries are given as n-ary queries based on runs of tree automata.