Theory of Computation (CS3800 12S) homepage

You have reached the webpage for the Northeastern University, College of Computer and Information Science, Spring 2012 session of Theory of Computation, also known as "CS3800 12S." This is an undergraduate course on the theory of computation. It serves as an introduction to formal models of languages and computation. Topics covered include finite automata and regular languages, pushdown automata and context-free languages, Turing machines, computability, and NP-completeness.

This course meets 1:35 pm - 3:15 pm TF West Village H 110
The instructor is Emanuele Viola. Email: (instructor's five-letter last name)@ccs.neu.edu.
Office hours, West Village H 246.
Part-time Teaching Assistant: Eric Miles, West Village H 266. Office hours: held in the lounge outside room 208 Thursday 11 - 12:30. Email: enmiles@ccs.neu.edu

This page, especially the problem sets below, will be modified from time to time; be sure to reload documents on occasion and check the "last modified" date against any printed version you may have.

Contents

• Announcements, including problem sets (below),


• Course outline (further below),


• Course information (even further below).

Announcements, including problem sets

2012-02-10 Friday QUIZ 1.

2012-03-02 Friday QUIZ 2.

2012-03-13 Tuesday Mid-course survey.

2012-03-30 Friday QUIZ 3.

2012-04-20 Friday Extra office hours 1:35 pm - 3:15 pm.

2012-04-23 Monday QUIZ 4, 8:00 am - 10:00 am, Shillman Hall 105

Quiz sample.

Note: You should pick up your graded homework and quizzes during the TA's office hours. This gives you an opportunity to discuss solutions and any corrections.

Problem Set 1. Assigned on 1/20, due on 1/27.
1: Exercise 1.6 parts: b, c, d, and e.
2: Give the formal definition of the DFA pictured in Exercise 1.21, (b). Show that this DFA accepts the string aab using the formal definition of accepting seen in class. For your reference, this definition is on Slide 45 and also in the book on Page 40.

Problem Set 2. Assigned on 1/27, due on 2/3.
1: Exercise 1.16.
2: Exercises 1.8 part a, 1.9 part a, and 1.10 part a.

Problem Set 3. Assigned on 2/17, due on 2/24.
1: Exercise 1.21.
2: Exercises 1.29(b).
3: Use the pumping lemma for regular languages to show that the following language is not regular: L = {aⁱ b ^j | i > 3j }.
4: Exercise 2.4, part b, part c, and part e.
5: Exercise 2.9.
6: Consider the following CFG grammar: S -> aSaS | aSa | ε. Show that the grammar is ambiguous.

Problem Set 4. Assigned on 3/16, due on 3/23.
The next exercises refer to the file Quiz sample.
22: (b) and (c).
27: (c) and (d).
34: (a) and (e).
36: (b).

Problem Set 5. Assigned on 4/6, due on 4/13.
The next exercises refer to the file Quiz sample.
39: (c) and (d).
46: (d).
47: (e).

Course outline

Course information

Prerequisites

• CS2510, Fundamentals of Computer Science 2
• CS2800, Logic and Computation

Text

• Required: Introduction to the Theory of Computation, Second Edition, by Michael Sipser.

Homework

• Start early: Difficult problems are not typically solved in one sitting. Start early and let the ideas come to you over the course of a few days.
• Be rigorous: CS3800 is a theory course, and as such, a certain level of mathematical rigor will be expected in your solutions.
• Be concise: Express your solutions at the proper level of detail. Give enough details to clearly present your solution, but not so many that the main ideas are obscured.
• Work with others: Some of the problems will be difficult, and it will often be helpful to discuss them with others. Feel free to form study groups. However, the idea is for everyone to understand the problems and experience working through the solutions, so you may not simply "give" a solution to another classmate. In particular, each student must write up his or her own homework solutions and must not read or copy the solutions of others. If you work with others on a problem, you must note with whom you discussed the problem at the beginning of your solution write-up.

Grading

• Quizzes: 80%
• Homework: 20%