1. 1 Welcome to Automata Theory Course Why Study Automata? What the Course is About

2. uInstructor: Cengiz Örencik uE-mail: cengizorencik@beykent.edu.tr uCourse material umyweb.sabanciuniv.edu/cengizo/courses Course info

3. Grading uMidterm 25% uInclass quizes (2)25% uFinal50% uHws wSelf study wNot be graded 3

4. 4 Why Study Automata? uRegular expressions are used in many systems. wE.g., UNIX a.*b. wE.g., Describe XML tags with a RE format like person (name, addr, child*). uFinite automata model protocols, electronic circuits.

5. 5 Why? – (2) uContext-free grammars are used to describe the syntax of essentially every programming language. wNot to forget their important role in describing natural languages.

6. 6 Why? – (3) uWhen developing solutions to real problems, we often confront the limitations of what software can do. wUndecidable things – no program whatever can do it. wIntractable things – there are programs, but no fast programs. uAutomata theory gives you the tools.

7. 7 Course Outline uRegular Languages and their descriptors: wFinite automata, nondeterministic finite automata, regular expressions. wAlgorithms to decide questions about regular languages, e.g., is it empty? wClosure properties of regular languages.

8. 8 Course Outline – (2) uContext-free languages and their descriptors: wContext-free grammars, pushdown automata. wDecision and closure properties.

9. 9 Course Outline – (3) uRecursive and recursively enumerable languages. wTuring machines, decidability of problems. wThe limit of what can be computed. uIntractable problems. wProblems that (appear to) require exponential time. wNP-completeness and beyond.

10. 10 Text (Not Required) uHopcroft, Motwani, Ullman, Automata Theory, Languages, and Computation 3 rd Edition.