CMPSCI 601: Theory of Computation
David Mix Barrington
To see the Spring 2003 CMPSCI 601 home page look
This is the home page for CMPSCI 601.
CMPSCI 601 is the graduate core course in
the theory of computation and will deal with formal
languages, computability, logic, and complexity theory.
Important Course Material (under
Announcements (14 May 2004):
- (14 May) Hardcopy HW#8 solutions are in the CMPSCI 601 pickup
box in the CMPSCI main office.
- (11 May) Ok, Lecture 27 notes are up.
- (11 May) Some questions and answers on HW#8
are up. Lecture notes for tomorrow's review lecture will follow later tonight.
- (9 May) Lecture 26 is up.
- (6 May) The HW#8 assignment is up, due
the last day of classes, Thursday 13 May, at 4:30 p.m. EDT
(time corrected 9 May).
- (5 May) Lecture 25 is up. I'll
try to post the HW#8 assignment (due 13 May 2004) by tonight.
- (4 May) I've gotten a lot of good questions on HW#7, which I'll
put on the Q&A page as soon as I can. In the meantime
I've made some clarifying remarks on the HW#7
assignment page. The only real "correction" as such is that I closed
the dangling right parenthesis in Question 5, so that you must prove the
result for all the NCi, ACi, and ThCi
classes except for NC0.
- (2 May) Tomorrow's Lecture 24 is up.
- (1 May) I have posted the first two
questions and answers on HW#7. I'll add more as they arrive.
- (30 Apr) I have a conflict for most or all of my office
hours tomorrow (Friday) at 2:30-3:30. I will be around for most
or all of the morning (9-12) and would be happy to discuss the
- (28 Apr) Lecture 23 and the
HW#7 assignment are now up. Sorry the
lecture wasn't available sooner.
- (25 Apr) Lecture 22 is now really
up. Several questions and answers on HW#6
are now up as well.
- (22 Apr) Lecture 21 is up.
The reference to Lecture 22 here earlier was a mistake.
I also corrected another typo on HW#6, "MEMBER-MP" where I meant
"MEMBER-NP". (Thanks to a different student for spotting this one.)
- (21 Apr) I've corrected a mistake on Question #4 of
HW#6. The Lecture 21 notes will be ready
later tonight -- in the meantime you may look at the similar
Lecture 20 notes from last year.
- (19 Apr) The HW#6 assignment and the
Lecture 20 notes are now available.
Note that this week our two lectures are on Wednesday and Thursday, as
Thu 22 April is a Monday schedule at UMass. The homework
index page and the lecture index page now have
links to the remainder of the hw's and lectures for the term, and thus
include the due dates of the hw's and the titles of the lectures. I'll
continue to let you know here when the pages become available.
- (13 Apr) Lecture 19 is now up.
- (13 Apr) I now have some questions and
answers on HW#5.
- (11 Apr) Lecture 18, for tomorrow,
is now available. Sorry I didn't get this up more in advance of the
lecture. If you want an idea of what is going to be presented in advance
of my notes, look at last year's notes.
For the rest of the term Lecture #n of this year will be pretty close
to Lecture #n-1 of last year.
- (11 Apr) It's been pointed out to me that I've now given two different
weightings of the midterm and final, 25/40 and 30/35. The only fair thing
to do is to give each of you whichever weighting turns out to be better for
you, so that's what I'll do.
- (6 Apr) The HW#5 assignment is now up,
due a week from Friday, 16 April 2004.
- (6 Apr) Sorry that I have been behind in lecture notes and in posting
the HW#5 assignment -- I have just put up
- (6 Apr) I have graded the on-campus midterms and will return them
before class tomorrow morning. I set the scale at 90 for the middle of the
A range and 60 for the middle of the B range. Scores were:
- A range (81-95): 12 students, high was 97
- AB range (66-80): 13 students
- B range (51-65): 12 students
- below B (0-50): two students, each of whom should talk to me
Students in the B range still have a good chance of an AB in the course
if their homework is strong. This exam is 25% of the grade, the final is
40%, and the best seven of eight hw's are 5% each.
- (3 Apr) I am back from Germany and ready to start grading your
exams. (I may finish this by Monday.) Thanks to Prof. Immerman
for covering last Wednesday's lecture.
notes were somewhat different
from the ones I posted before I left.
The last several slides on those notes are material that he didn't get
to, so they are repeated on the Lecture 16 notes.
- (24 Mar) I've just posted several questions
and answers on HW#4.
- (24 Mar) As I mentioned in lecture, I'll be in Germany all next
week, though I will have access to email. The TA's will proctor the in-class
exam on Monday, and Prof. Immerman will give the lecture on Wednesday.
- (22 Mar) Notes for Lecture 14 are now up.
- (22 Mar) There is a pickup box for CMPSCI 601 in the main department
office, in a gray filing cabinet to the left of Pauline's desk as you go in.
It has graded homework not picked up in class, and also hardcopy homework
solutions. Half the HW#3 solutions were made available in class today, and
the other half will go into the folder soon. The graders will try hard to
have HW#4 solutions there before the end of the day Friday.
- (22 Mar) The HW#2 performance from on-campus students was strong.
There were 19 results in the 100's (because of the extra credit), 11 in the
90's, three in the 80's, four in the 70's, and one in the 50's.
- (22 Mar) As I mentioned in lecture today, I have written three
CMPSCI 601 midterms in the last year, for the
Summer 2003, and
Fall 2003 terms. The summer
and fall exams are probably easier than the spring one, which is the best
model for your upcoming midterm.
- (17 Mar) I'll be out of town and unreachable Friday, Saturday,
and Sunday (19-21 March).
- (17 Mar) I have now posted Lecture 13,
the start of a short unit on first-order logic. Lectures 14, 15, and 16
will follow [BE] fairly closely as we prove soundness (18.3) and completeness
(Chapter 19) of the full Fitch proof system for FOL.
The exam will probably have a question about FOL for Tarski's world
like the one from last year's
exam. There may also be questions about Lectures 13 and 14.
- (12 Mar) I have just posted HW #4, due
for on-campus students a week from Friday. Forty of the 100 points are
questions on Lectures 11 and 12, and sixty are problems from [BE].
Most of the latter can be done before Lectures 13 and 14 if you want to
work on them over break.
- (12 Mar) The midterm will be in class on Mon 29 March. Here is
my midterm from Spring 2003
and solutions for it. This
term's midterm will be fairly similar to this, covering Lectures 1-14.
- (9 Mar) I have just posted several more questions and answers
about HW#3 on the q&a page.
- (9 Mar) The Jeffrey Amherst Bookstore inform me that they
will return their unsold copies of the textbooks for this course during
the next week or two. They have copies of [BE], Papadimitriou, and Sipser
on the shelf now.
- (9 Mar) I am delaying the off-campus due date for HW#3
until Mon 22 March at 2:00 p.m. EST. HW#4 will be posted soon and
due for on-campus students after spring break, Fri 26 March, also
at 2:00 p.m. EST. I'll make solutions available by hard-copy to on-campus
students at that time, but we clearly won't grade HW#4 before the midterm
which is in class Mon 29 March at 10:35 a.m. EST.
- (8 Mar) Notes for Lecture 12, the
last lecture before spring break, are now up.
- (5 Mar) There are now some questions and answers
on HW#3 posted. Question 6 on HW#3 may be easier after Lecture 11,
which has an example of a proof about all Bloop-computable functions.
- (5 Mar) I have now posted Lecture 11,
for next Monday. Lecture 12 will follow later today or over the weekend.
- (3 Mar) Graded HW#1 for on-campus students was returned today.
If you have questions about the grading, please contant Alex (adingle@cs,
Thu 2:30-3:30) about
questions 1-4 and Stephen (shart@cs, Wed 1-2) about 5-8. TA office hours
are in LGRT 220, near the EdLab.
The average score was 73, with one 100+, four 90-99, ten 80-89, four
70-79, twelve 60-69, four 50-59, and two under 50. The middle of the A
range will be about 85-90 and the middle of the AB range about 65-70.
- (1 Mar) I have just put up Lecture 10
and Homework #3. The latter is due 10 March, a
week from Wednesday. I tried to make it shorter than the first two.
- (26 Feb) Lecture 9 is now up.
I may be delayed in preparing Lecture 10 -- if you would like to read
ahead I can tell you that it will be similar to
last year's Lecture 7.
- (22 Feb) I now have some questions and
answers on HW#2, and I will add to this page as more come in.
- (22 Feb) Lecture 8 is now up.
Hard copies of the rest of the HW#1 solutions should be available
in class tomorrow.
- (21 Feb) I have replaced the last question on
Homework #2, so please download it again if you have only have the old
version. This question depends on the material of Lecture 8, so I doubt anyone
has started on it. I'll announce this in class on Monday as well.
- (21 Feb) Lecture 7, for Monday 23
February, is now up. Lecture 8 will follow today or tomorrow.
- (17 Feb) I've just posted the HW#2
assignment, which is 80% from [BE] dealing with the material
of Lectures 5 and 6. The other 20% deal with Lectures 7 and 8.
- (17 Feb) There are several more questions answered about HW#1
here. A reminder that HW is due on paper
and in class. We'll probably hand out hardcopy solutions after
the class -- we can't put solutions on the web because the off-campus
students have another week to do HW#1.
- (15 Feb) I have posted Lecture 6,
for this coming Wednesday. The HW#2 assignment, which will be partly from
[BE], will be posted before Wednesday. The Lecture Notes
Directory page now has the tentative titles of the lectures up to spring
- (9 Feb) I have finally set office hours for me and for the TA's:
- Dave: Tuesdays 9-11:30, Friday 2:30-3:30 in room 210 CMPSCI
- Stephen Hart: Wednesdays 1-2, location TBA
- Alex Dingle: Thursdays 2:30-3:30, location TBA
- (9 Feb) If you want to test the homework submission functions
of the [BE] software, use Alex' email address
email@example.com. He will be taking submissions for
- (8 Feb) Lecture 5, for this coming
Wednesday, is now posted. Remember that Monday 16 February is a holiday,
so that Lecture 6 will be on Wednesday 18 February.
- (6 Feb) Both Lectures 5 and 6
will deal with propositional logic: 5 with its syntax and semantics
and with the rules of the Fitch proof system, and 6 with the soundness
and completeness of propositional Fitch and a few related topics.
I've not forgotten that I owe you a syllabus as well.
- (5 Feb) Lecture 4 is now posted.
Lecture 5 should follow fairly soon. The latter will deal with chapters
1-8 and 17 of [BE], so you should read these and determine how much of
the material (on propositional logic) is review for you.
- (1 Feb) The first student question on HW#1, and my answer, are
now posted here. Pretty good football game, eh?
- (30 Jan) Lecture 3 is now posted,
- (29 Jan) Lecture 2 is now posted,
I hope to post Lecture 3 tonight or tomorrow. If this is new material
for you, you will want to look at Sipser, chapter 1, or another reference
on finite automata.
- (28 Jan) It turned out that the snow was less than expected
and we had class as scheduled. I'll let you know when Lectures 2 and
3 are posted -- they will be similar to lectures 1 and 2 from Spring 2003.
- (27 Jan) The HW#1 assignment is now
posted, due three weeks from tomorrow. Many questions deal with the
models of computation defined in Lecture 1,
and the later ones deal with Lectures 2-4.
- (27 Jan) There is serious snow
forecast for tomorrow's opening class. I will hold class if and only
if the University is open by 10:35 -- check
this page for the latest.
In particular, if UMass opens at 11:00 there will be no class.
- (26 Jan) I have just posted Lecture 1.
In general I will try to get notes posted a day or two before each lecture
is delivered. I hope to get HW#1 posted later today.
- (21 Jan) I am just starting construction of the site for the
new offering of the course today. In most respects the course will
follow the model of the Spring 2003 version, whose web page is
The most important change is in the textbook. The only required
text is Barwise and Etchemendy, Language, Proof, and Logic
(University of Chicago Press, 2002).
(I have ordered copies of this at the
Jeffrey Amherst College Bookstore.) Some of the homework (starting
with HW#2 rather than HW#4 as last year) will be graded electronically
by the website for this book. You will thus need a new copy, unless
you bought the book before for a different course.
The Papadimitriou text, Computational Complexity (Addison-Wesley,
1994), is now recommended rather than required. We will largely use this
book's notation in lecture, but the primary text will be the
lecture notes available on-line.
Sipser's Introduction to the Theory of Computation (PWS, 1997)
is also a useful
reference, particularly on the basic formal language material that you might
or might not have seen in an earlier course.
Last modified 14 May 2004