Language and Automata Theory and Applications

These proceedings contain all the papers that were presented at the Third - ternational Conference on Language and Automata Theory and Applications (LATA 2009), held in Tarragona, Spain, during April 2-8, 2009. The scope of LATA is rather broad, including: algebraic language theory; algorithms on automata and words; automata and logic; automata for s- tem analysis and program veri?cation; automata, concurrency and Petri nets; biomolecular nanotechnology; cellular automata; circuits and networks; c- binatorics on words; computability; computational, descriptional, communi- tion and parameterized complexity; data and image compression; decidability questions on words and languages; digital libraries; DNA and other models of bio-inspired computing; document engineering; extended automata; foundations of ?nite-state technology;fuzzy and roughlanguages;grammars(Chomsky hi- archy,contextual, multidimensional, uni?cation, categorial,etc. ); grammarsand automata architectures; grammatical inference and algorithmic learning; graphs and graph transformation; language varieties and semigroups; language-based cryptography;language-theoreticfoundationsofnaturallanguageprocessing,- ti?cial intelligence and arti?cial life; mathematical evolutionary genomics; pa- ing;patternsandcodes;powerseries;quantum,chemicalandopticalcomputing; regulated rewriting; string and combinatorial issues in computational biology and bioinformatics; symbolic dynamics; symbolic neural networks; term rewr- ing; text algorithms; text retrieval, pattern matching and pattern recognition; transducers; trees, tree languages and tree machines; and weighted machines. LATA 2009 received 121 submissions, many among them of good quality. Each one was reviewed by at least three Program Committee members plus, in mostcases,byadditionalexternalreferees. Afterathoroughandvividdiscussion phase, the committee decided to accept 58 papers (which means an acceptance rate of 47. 93%).