CS154Spring 2007Sec3Home Page/Syllabus

Formal Languages and Computability

This course covers the basics of finite automata, context-free languages, Turing machines, computability. Finite automata are used in the lexical analysis part of a compiler, and are also used for string matching, and for simple AIs in video games. Context-free languages are used for parsing in compilers. XML is a currently trendy language for defining essentially context-free languages. Computability is the study of what it is possibility to get a computer to do. In computability theory, we use an abstract model of a computer called a Turing Machine and study what it can and cannot do. By the end of this course, you should be able to: (1) Write a grammar for a language described otherwise. (2) Construct deterministic and non-deterministic machines for various languages. (3) Describe a language in terms of a regular expression. (4) Find a regular expression for a language described by a finite automaton and conversely. (5) Construct a deterministic finite automaton from a non-deterministic one. (6) Minimize a deterministic automaton. (7) Be able to use a pumping lemma to show that some languages are not regular and/or not context-free. Use closure properties to simplify proofs of non-regularity of languages. (8) Be able to construct a pushdown automaton accepting a given language. (9) Construct a Turing machine accepting some simple languages. (10) State in precise mathematical terms what is meant by undecidability of the Halting Problem, and be able to show the undecidability of simple extensions of the Halting Problem, using the reduction technique.

Below is a tentative time table for when we'll do things this quarter:

Grades will be calculated in the following manner: The person or persons with the highest aggregate score will receive an A+. A score of 55 will be the cut-off for a C-. The region between this high and low score will be divided into eight equal-sized regions. From the top region to the low region, a score falling within a region receives the grade: A, A-, B+, B, B-, C+, C, C-. If the boundary between an A and an A- is 85, then the score 85 counts as an A-. Scores below 55 but above 50 receive the grade D. Those below 50 receive the grade F

If you do better than an A- in this class and want me to write you a letter of recommendation, I will generally be willing provided you ask me within two years of taking my course. Be advised that I write better letters if I know you to some degree.

Links to the current list of assignments can be found on the left hand frame of the class homepage. After an assignment has been returned a link to its solution (based on the best student solutions) will be placed off the assignment page. Material from assignments may appear on midterms and finals. For homeworks you are encouraged to work in groups of up to three people. Only one person out of this group needs to submit the homework assignment; however, the members of the group need to be clearly identified in all submitted files. Homeworks for this class will be submitted and returned completely electronically. The written and programming parts of an assignment are submitted by clicking on the submit homework link for your section on the left hand side of the homepage and filling out the on-line form. Hardcopies or e-mail versions of your assignments will be rejected and not receive credit. Homeworks will always be due by the start of class on the day their due. Late homeworks will not be accepted; however, your low homework score will be dropped.

The midterms will be during class time on: Mar 7 and Apr 18.

The final will be: Tuesday, May 22 from 9:45am to 12:00pm.

All exams are closed book, closed notes and in this classroom. You will be allowed only the test and your pen or pencil on your desk during these exams. Beeper or cell-phone interruptions will result in immediate excusal from the test. The final will cover material from the whole quarter although there will be an emphasis on material after the last midterm. No make ups will be given. The final exam may be scaled to replace a midterm grade if it was missed under provably legitimate circumstances. These exams will test whether or not you have mastered the material both presented in class or assigned as homework during the quarter. My exams usually consist of a series of essay style questions. I try to avoid making tricky problems. The week before each exam I will give out a list of problems representative of the level of difficulty of problems the student will be expected to answer on the exam. Any disputes concerning grades on exams should be directed to me, Professor Pollett.

If you believe an error was made in the grading of your program or exam, you may request in person a regrade from me, Professor Pollett, during my office hours. I do not accept e-mail requests for regrades. A request for a regrade must be made no more than a week after the homework or a midterm is returned. If you cannot find me before the end of the semester and you would like to request a regrade of your final, you may see me in person at the start of the immediately following semester.

The campus policy to ensure compliance with the Americans with Disabilities Act is:
"If you need course adaptations or accommodations because of a disability, or if you need special arrangements in case the building must be evacuated, please make an appointment with me as soon as possible, or see me during office hours. Presidential Directive 97-03 requires that students with disabilities register with DRC to establish a record of their disability."

More information about SJSU policies and procedures can be found at the following links: