Developments in Language Theory

Since 1993 the conference Developments in Language Theory (DLT) has been held in Europe every odd year and, since 2002, outside Europe every even year. The 13th conference in this series was DLT 2009. It took place in Stuttgart fromJune30to July3.PreviousmeetingsoccurredinTurku(1993),Magdeburg (1995),Thessaloniki(1997),Aachen(1999),Vienna(2001),Kyoto(2002),Szeged (2003), Auckland (2004), Palermo (2005), Santa Barbara (2006), Turku (2007), and Kyoto (2008). The DLT conference has developed into the main forum for language theory and related topics. This has also been re?ected in the high quality of the 70 s- missions received in 2009. Most submissions were reviewed by four Programme Committeemembersandtheirsub-referees.TheProgrammeCommitteeselected the best 35 papers for presentation during the conference. These 35 papers are also published in this proceedings volume. Members of the ProgrammeComm- tee were not allowed to submit papers. The work of the Programme Committee wasorganizedusingtheEasyChairconferencesystem,thankstoAndreiVoronkov. The conference programme included ?ve invited lectures. They were given by Mikola j Bojanczyk (Warsaw), Paul Gastin (Cachan), Tero Harju (Turku), ChristosKapoutsis(Nicosia),andBenjaminSteinberg(Ottawa).Wearegrateful to the invited speakers for accepting the invitation and presenting their lectures and for their contributions to the proceedings. The Informatik Forum Stuttgart provided a best paper award, which was selected by the Programme Committee. The recipient was: Magic Numbers and Ternary Alphabet by Galina Jiraskova.

Inhalt
Invited Talks.- Factorization Forests.- Weighted versus Probabilistic Logics.- Post Correspondence Problem and Small Dimensional Matrices.- Size Complexity of Two-Way Finite Automata.- Matrix Mortality and the ?erný-Pin Conjecture.- Regular Papers.- A Quadratic Upper Bound on the Size of a Synchronizing Word in One-Cluster Automata.- Regular Languages Definable by Majority Quantifiers with Two Variables.- The Inclusion Problem of Context-Free Languages: Some Tractable Cases.- On the Complexity of Deciding Avoidability of Sets of Partial Words.- Closures in Formal Languages and Kuratowski's Theorem.- Rich and Periodic-Like Words.- Traces of Control-Flow Graphs.- Left and Right Synchronous Relations.- An Extension of the Lyndon Schützenberger Result to Pseudoperiodic Words.- Asymptotic Cellular Complexity.- Strongly Regular Grammars and Regular Approximation of Context-Free Languages.- Powers of Regular Languages.- Existence and Nonexistence of Descriptive Patterns.- On Stateless Multihead Finite Automata and Multihead Pushdown Automata.- On Negative Bases.- Crucial Words for Abelian Powers.- Tight Bounds on the Descriptional Complexity of Regular Expressions.- Subshifts, Languages and Logic.- Magic Numbers and Ternary Alphabet.- The Pumping Lemma for Well-Nested Multiple Context-Free Languages.- The Support of a Recognizable Series over a Zero-Sum Free, Commutative Semiring Is Recognizable.- A Game-Theoretic Characterization of Boolean Grammars.- Word Equations with One Unknown.- On Equations over Sets of Numbers and Their Limitations.- Some Remarks on Superposition Based on Watson-Crick-Like Complementarity.- A Weighted ?-Calculus on Words.- Branching-Time Temporal Logics with Minimal Model Quantifiers.- Simulations by Time-Bounded Counter Machines.- WeightedTimed MSO Logics.- Balanced Words Having Simple Burrows-Wheeler Transform.- On the Complexity of Hmelevskii's Theorem and Satisfiability of Three Unknown Equations.- Definability in the Infix Order on Words.- Two-Sided Bounds for the Growth Rates of Power-Free Languages.- On the Decidability of the Equivalence for a Certain Class of Transducers.- Erasing in Petri Net Languages and Matrix Grammars.