Automata-Theoretic Aspects of Formal Power Series

I. Introduction.- I.1. Preliminaries from algebra and analysis.- I.2. Preliminaries from automata and formal language theory.- I.3. Formal power series in noncommuting variables.- II. Rational series.- II.1. Rational series and linear systems.- II.2. Recognizable series.- II.3. Hankel matrices.- II.4. Operations preserving rationality.- II.5. Regular languages and rational series.- II.6. Fatou properties.- II.7. On rational series with real coefficients.- II.8. On positive series.- II.9. Rational sequences.- II.10. Positive sequences.- II.11. On series in product monoids.- II.12. Decidability questions.- III. Applications of rational series.- III.1. On rational transductions.- III.2. Families of rational languages.- III.3. Rational series and stochastic automata.- III.4. On stochastic languages.- III.5. On one-letter stochastic languages.- III.6. Densities of regular languages.- III.7. Growth functions of L systems: characterization results.- III.8. Growth functions of L systems: decidability.- IV. Algebraic series and context-free languages.- IV.1. Proper algebraic systems of equations.- IV.2. Reduction theorems.- IV.3. Closure properties.- IV.4. Theorems of Shamir and Chomsky-Schiitzenberger.- IV.5. Commuting variables and decidability.- IV.6. Generalizations of proper systems. Fatou extensions.- IV.7. Algebraic transductions.- Historical and bibliographical remarks.- References.