# LSV Seminar

The LSV seminar takes place on Tuesday at 11:00 AM. The usual location is the conference room at Pavillon des Jardins (venue).
If you wish to be informed by e-mail about upcoming seminars, please contact Stéphane Le Roux and Matthias Fuegger.

The seminar is open to public and does not require any form of registration.

## Past Seminars

### Model Theory of XPath with data tests

- Date
- Tuesday, September 30 2014 at 11:00AM
- Place
- Salle de Conférence (Pavillon des Jardins)
- Speaker
- Santiago Figueira (University of Buenos Aires)

We develop the basic model theory of XPath with data (in)equality
tests over the class of data trees, i.e., the class of trees where
each node contains a label from a finite alphabet and a data value
from an infinite domain. We provide notions of bisimulations (both
general and bounded) for XPath logics containing only 'child', or both
'child' and 'parent' navigational axes. We show that these notions
precisely capture the logical equivalence relation associated with
each fragment, and show two results where the tool of bisimulation
plays a central role: characterization and definability. The former
says that certain logic is the bisimulation-invariant fragment of
first order; the latter gives necessary and sufficient conditions for
a class of pointed data trees to be definable by a set of formulas or
by a single formula.