18.404/6.840
Theory of Computation
Due in E17131 by 2:30pm sharp, Thursday, October 8, 2015
Michael Sipser
Problem Set 2
Please turn in each problem on a separate page with your name.
Real all of Chapters 3 and 4.
1. Let = cfw_0, 1, #. Let C = cfw_x#xR #x

18.404/6.840
Theory of Computation
Due in E17131 by 2:30pm sharp, Thursday, October 22, 2015
Michael Sipser
Problem Set 3
Please turn in each problem on a separate page with your name.
Read all of Chapter 5 and Section 6.1.
1. Consider the problem of dete

18.404/6.840
Theory of Computation
Due in E17131 by 2:30pm sharp, Thursday, September 24, 2015
Michael Sipser
Problem Set 1
Please turn in each problem on a separate page with your name.
Real all of Chapters 1 and 2 except Section 2.4.
0.1 Read and solve,

18.404/6.840
Theory of Computation
Due in E17131 by 2:30pm sharp, Thursday, November 19, 2015
Michael Sipser
Problem Set 5 revised 11/4/15
Please turn in each problem on a separate page with your name.
1. This problem is inspired by the single-player game

18.404/6.840
Theory of Computation
Due in E17131 by 2:30pm sharp, Thursday, December 3, 2015
Michael Sipser
Problem Set 6
Please turn in each problem on a separate page with your name.
1. (a) Let ADD = cfw_ x, y, z | x, y, z > 0 are binary integers and x

18.404/6.840
Theory of Computation
Due in E17131 by 2:30pm sharp, Thursday, November 5, 2015
Michael Sipser
Problem Set 4
Please turn in each problem on a separate page with your name.
1. Let MODEXP = cfw_ a, b, c, p | a, b, c, p are positive binary integ

18.404/6.840 Fall 2015
Theory of Computation
Michael Sipser
Solutions to Sample Midterm Questions
1. (a)
On input w:
1. Read as and push onto the stack until the rst non-a.
2. Nondeterministically branch to either 3 or 4.
3. Read bs and match with as popp

Theory of Computation
18.404/6.840
Fall 2015
Michael Sipser
Sample MidTerm Examination Questions
1. (a) Let = cfw_a, b, c and let A = cfw_ai bj ck | i, j, k 0, and i = j or i = k.
Describe (in English) a pushdown automaton that recognizes A.
(b) Let R be