CS150 Homepage

HW4 has been posted, due on Thursday, 5/20, at 3pm.
HW3 solutions are posted.
Please subscribe to the class mailing list ASAP, via the link at the bottom of the page.

Syllabus : PDF.

Instructor :

Tao Jiang (jiangATcs.ucr.edu)
Office hours: TR 1-2pm. Office: WCH 336. Zoom meeting info can be found in the syllabus.

Teaching Assistants and office hours:

TA: Amir Nodehi Sabet (anode001ATucr.edu). Office hours: M 3-4pm.
Reader: Peter Tran (ptran108ATucr.edu). Office hour: TBA.
Reader: Shiyi Zhang (szhan251ATucr.edu). Office hour: TBA.
TA/reader office hours are held in WCH 110 unless otherwise stated (actually via Zoom this quarter). The Zoom meeting info can be found in the syllabus.

UCR Academic Resources Center (ARC):

It provides peer-led supplemental instruction, tutoring, writing support, and study skills workshops for students who want to excel in their studies, as well as for students who are having difficulty in their courses. The reception room for the ARC is located in Room 156 of the Skye Hall. See its Tutorial Assistance Program homepage for more details. Remote tutoring is available in S21 by appointments and begins on April 5.


TR 3:30-4:50pm online via Zoom. Please register in advance for this meeting. After registration, you will receive a confirmaation email containing information about joining the meeting.

Previous lectures on 3/30, 4/1, 4/6, 4/8, 4/13, 4/15, 4/20, 4/22, 4/27, 4/29, 5/4, 5/6

Discussion Sessions:

Dis 021, W 6:00 - 6:50pm, online (via Zoom; meeting ID in the syllabus), Amir Nodehi Sabet


Introduction to Automata Theory, Languages, and Computation, 3rd Edition by J. Hopcroft, R. Motwani and J. Ullman, 2007, Pearson.

The book is available for purchase/rent via the Internet. Relevant chapters of the book can also be found on iLearn. The following webpage maintained by the authors of the textbook offers many errata and sample solutions to selected exercises:
Textbook Homepage

Reference Books:

Introduction to Formal Languages and Automata, 6th Edition, 2017 by P. Linz.
Introduction to Theory of Computation, 2019 by A. Maheshwari and M. Smid.

Lecture Notes:

Please download the following lecture notes and bring them to the lectures. The original lecture notes were provided at the textbook homepage courtesy of G. Grahne and J. Ullman, although extensive updates have been made by TJ.
Main lecture notes on automata and formal languages.

If you find working with a big set of slides intimidating, I have broken them up roughly according to our weekly topics below. However, these notes are not as up-to-date as the main notes. Please consult the tentative time table in the syllabus for the weekly schedule of our lectures and the chapters covered in the text and reference books.
Slides for week 1: Introduction, DFA and NFA.
Slides for week 2: REX and equivalence among DFA, NFA and REX.
Slides for week 3: Algebraic laws for REX and pumping lemma for RL.
Slides for week 4: RL properties and minimization of DFA.
Slides for week 5: CFG and CFL.
Slides for week 6: CFG parsing and ambiguity.
Slides for week 7: Various forms of PDA and their equivalence to CFG.
Slides for week 8: Chomosky normal form.
Slides for week 9: Pumping lemma, closure properties and the CYK algorithm.
Slides for week 10: Introduction to undecidability and Turing machines.

Here are two chapters that we wrote for the Algorithms and Theory of Computation Handbook some years ago:
Formal Grammars and Languages
These chapters are not very technical and may help provide some high-level concepts about the theory. The following article in a 2015 issue of Communications of the ACM provides some technical perspective on the question of how to decide the equivalence of NFAs and could also be interesting to read:
The Equivalence Problem for Finite Automata
One may also find the following topic interesting:
The Smallest Grammar Problem

Homework Assignments:

HW1 and solution keys
HW2 and solution keys
HW3 and solution keys

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The following mapping shows how your overall scores will be translated into letter grades at the end of the quarter: 90+ -> A+, 85+ -> A, 80+ -> A-, 77+ -> B+, 73+ -> B, 70+ -> B-, 67+ -> C+, 63+ -> C, 60+ -> C-, 57+ -> D+, 53+ -> D, 50+ -> D-, 49- -> F.