CPSC 421/501 Page, Fall 2014

This page concerns CPSC 421 Section 101 and CPSC 501 Section 101. The courses have been combined, except that CPSC 501 will have an additional essay to write.

This page has the most up-to-date information on the course(s) and supersedes any other document. Not all course material are available at all times (especially solution sets to homeworks).

Overview Overview for this course. The main text for this course is Theory of Computation, by Michael Sipser, 3rd Edition. We shall begin the course with a handout Computability and Self-Referencing in CPSC421; this is a more general (and leisurely) treatment of Section 4.2 of Sipser's textbook, that doesn't require knowing how a Turing machine works. We will then cover Turning machines, parts of Chapters 3-7 and 9; regular languages (Chapter 1) and context-free languages (Chapter 2) will be covered briefly towards the end of the course.
Final Exam The final exam for this class will take place on December 3 at 8:30am.
Sample Exams We have a new document describing our coverage of Sipser Chapters 8 and 9, and giving sample exam problems (some of which are assigned for homework). All the homework problems, and all the problems in Computability and Self-Referencing in CPSC421 are good sample exam problems (some of the longer problems would be shortened or modified so as to be solvable more quickly). Here are some old exams, some with solutions:
  1. midterm 2010 (solutions),
  2. final 2010,
  3. midterm 2011 (solutions),
  4. final 2010,
  5. midterm 2014 (solutions). (This term, the midterm was scaled as follows: if your raw score on the midterm is r (out of 36 points), your scaled grade is 5r if r <= 10, and 2r+30 if r >= 10. Hence 10/36 yields a scaled mark of 50, and a 36/36 yields a scaled mark of 102.)
More sample midterm problems discusses the material covered by the midterm this term; this is the material in Computability and Self-Referencing in CPSC421, Sipser 3.1, 3.2, Our discussion of PALINDROME, 3.3 (Terminology for describing Turing machines), 4.2, 7.1, 7.2.
Handout We begin the course by talking about the Halting problem and related ``paradoxes'' with the handout Computability and Self-Referencing in CPSC421 (last modified September 27, 2014); these notes will be modified, and have material added to them (especially exercises). This material will be reviewed again later in the course (see Chapters 4 and 5 of Sipser's text).
Blogs I will write a blog to say roughly what we are covering when and to make some additional remarks regarding class material. This blog is usually quite skeletal, and will be modified throughout the term. I will summarize the topics in the handout and in Sipser's textbook here.
Homework All homework involving the text is based on the 3rd edition of Sipser's book.
Homework #1, due September 15: Problems 7.1.1, 7.1.2, 7.1.4, 7.1.9(3) of the handout. Graded out of 14 possible points. Solutions.
Homework #2, due September 22: Problems (7.1.4,) 7.1.5, 7.2.1, 7.2.3, 7.2.6. Graded out of 10 possible points. Solutions.
Homework #3, due September 29: Problem 7.3.1, for the language 421Simple, for Axiom 2; Problem 7.3.1, for the language 421Simple, for Axiom 4; 7.3.3(2), 7.3.4(2) (both 421Simple and a Turing Machine). Solutions.
Homework #4, due October 10: Sample Midterm Problems: 5,7,16,17. Solutions.
No more homework until a week after the midterm.
Homework #5, due November 10: Sipser's text: 7.22, 7.25, 7.29, 7.30.
Homework #6, due November 19: Problems 2, 6, 7 from our coverage of Sipser Chapters 8 and 9.
Homework #7 will not be collected or graded: Problems 9, 10, 12, 13 from our coverage of Sipser Chapters 8 and 9.
Homework #8 will not be collected or graded: Some problems on regular languages (Chapter 1 of Sipser's textbook): To Be Announced.
Office Hours Joel Friedman (Instructor): by appointment, unless posted otherwise. Office hours for the week of Oct 20-24: October 20, 9:20-10:20am in Mathematics Building, room 210, October 21, 7:45-8:50am CS Building (ICCS), room 304. Alireza Zakeri-Hosseinabadi (TA): Thursdays 5:30-6:30pm and Friday 4:30-5:30pm, both in ICCS, room X139.
Essay Students in CPSC 501 have an essay due on the last day of class. Choose any topic that goes beyond something done in this course, but please get my approval. The following topics are fine: (1) Fuller discussion of some of the paradoxes mentioned in the handout, including: Godel's incompleteness theorems and Russell's paradox; (2) Discussion of a number of different types of problems (including some that may arise in practice?) known to be undecidable or unacceptable (unrecognizable); (3) Methods of showing that a language is not recognizable (how many different methods are known, for example?); (4) Discuss the Chomsky Hierarchy (e.g., explain why Type-0 grammars yield precisely all Turing-recognizable languages, what Type-1 grammars (context sensitive) give) (see the wikipedia page);
Other News The textbook Computational Complexity: A Modern Approach, by Arora and Barak contains the "easy" PSPACE-complete language discussed in class, in Section 4.2, between Definitions~4.9 and 4.10.

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