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2. CSE2303 Formal Methods I Introduction David Albrecht Lecture 1

3. Overview Important information Language Examples Terminology Other things we will cover in the course.

4. Lecturer Dr. David Albrecht Room 113, Building 75 Tel: (x55526) Email:David.Albrecht@csse.monash.edu.au URL: http://www.csse.monash.edu.au/~dwa/

5. Text Books Prescribed Text: Daniel I.A. Cohen, “Introduction to Computer Theory”, Second Edition, John Wiley & Sons, 1997 Recommended Reading: Michael Sipser, “Introduction to the Theory of Computation”, PWS Publishing Company, 1997

6. Lectures, Pracs and Tutes Lectures are on the web Alternative weeks for tutes/pracs. Tutes (1 hour) Pracs (3 hours) Timetable: http://www.infotech.monash.edu.au/allocateplus

7. Assessment Pracs (30%) Exam (70%) Hurdles Pracs at least 50% overall and attend 5 out of the 6 pracs. Exam at least 50% Overall mark of at least 50%

8. Where to get Information Courseware Page Noticeboards –near General Office in Building 75 General Office Lecturer Newsgroup

9. Languages Natural Languages –English, Chinese, French, etc. Programming Languages –C, MIPS, BASIC, Fortran, Pascal, etc. Mathematics State Diagrams Music Feynman Diagrams

10. Components Alphabet –Basic elements Rules –Grammar –Tell you what words belong to the language –syntax Meaning –semantics

11. Definition Alphabet –Fundamental building blocks –set of letters or characters Language –set of strings of characters from the alphabet Word –a string of characters belonging to the language

12. English-Words Alphabet a b c.. z A B.. Z ’ - Words –all the words in a standard dictionary –e.g. don’t context-free regular …

13. English-Sentences Alphabet –English words –punctuation marks ? !, ‘ ’ ; : –blank space Words –sentences What is on the exam? The quick brown fox jumped over the lazy dog.

14. C Alphabet –ASCII characters Words –programs #include main(){printf(“Hello\n”);}

15. Conventions Alphabet a b Words a b ab abbb bab … Notation a 2 means aa b 3 means bbb Empty Word  Empty Language 

16. EVEN-EVEN All the strings that contain an even number of a ’s and an even number of b ’s. E.g.  aa bb aaaa aabb abab abba baab

17. PALINDROME All the strings which are the same if they are spelt backwards E.g.  a b aa bb aaa aba bab bbb

18. DOUBLEWORD All the strings are formed by two copies of a string joined together. { ss : s is a string of a and b } E.g.  aa bb aaaa abab baba bbbb

19. Halting Problem Consider the following problem: Design a program HALT which takes as input a program, P, and data, D, and returns true if P halts on the data D, and false otherwise.

20. Logic Languages Propositional Logic Predicate Logic

21. Along the Way Flex Bison Sequential Logic Circuits Turing Machines Prolog

22. Preparation Read –Text Book: Chapters 1-4.