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.