Fall 2021 Syllabus

**Room:** CCSB 1.0202

**General Prerequisites:** CS 2302 "Data Structures" and either
Discrete Mathematics or Discrete Structures, both with grades C or
higher.

**Alternative Prerequisites:** CS 2401 "Elementary Data
Structures and Algorithms" and either Discrete Mathematics or
Discrete Structures, both with grades B or higher.

**Instructor:** Vladik
Kreinovich, email vladik@utep.edu, office CCSB 3.0404,

office phone (915) 747-6951.

- The instructor's office hours are Tuesdays and Thursdays 1:30-3 pm, or by appointment.

- use the instructor's appointments page /vladik/appointments.html to find the time when the instructor is not busy (i.e., when he has no other appointments), and
- send him an email, to vladik@utep.edu, indicating the day and time that you would like to meet.

**Teaching Assistant (TA):** Laxman Bokati, email lbokati@miners.utep.edu,
office hours:

- in person Mondays 2-3 pm and 4-5 pm in CCSB 2.0108A,
- online Fridays 3-5 pm by MS Teams; send an email to the TA if you want to attend,
- or by appointment.

- Time Mondays and Wednesdays 12-1:20 pm.
- Dr. Longpre's email is longpre@utep.edu.

**Course Objectives:**
Theoretical computing models and the formal languages they
characterize: Finite state machines, regular expressions,
pushdown automata, context-free grammars, Turing machines and
computability. Capabilities and limitations of each model, and
applications including lexical analysis and parsing.

**Major Topics Covered in the Course**

- Regular languages, finite automata (FA), non deterministic FA (NFA)
- Context-free languages, pushdown automata (PDA)
- Parsing, normal forms, ambiguity
- Pumping lemmas and closure properties
- Turing machines and other equivalent models
- Decidable languages, non-decidable languages, recognizable languages, Chomsky hierarchy

**Level 1: Knowledge and Comprehension**

Level 1 outcomes are those in which the student has been
exposed to the terms and concepts at a basic level and can
supply basic definitions. The material has been presented only
at a

superficial level.

Upon successful completion of this course, students will be able to:

1a. Describe implications of Church-Turing thesis.

1b. Describe problems for which an algorithm exists, and problems for which there are no algorithms (non-recursive, non-recursively enumerable languages) and describe the implications of such results.

1c. Describe and explain the diagonalization process as used in proofs about computability.

1d. Describe the difference between feasible and non-feasible algorithms, describe the limitations of the current formalization of feasibility as polynomial-time.

1e. Describe the main ideas behind the concepts of NP and NP-hardness, know examples of NP-hard problems.

**Level 2: Application and Analysis**

Level 2 outcomes are those in which the student can apply the
material in familiar situations, e.g., can work a problem of
familiar structure with minor changes in the details.

Upon
successful completion of this course, students will be able to:

2a. Convert a non-deterministic FA (respectively transition graph) into an equivalent deterministic FA.

2b. Convert a transition graph or NFA into an equivalent regular expression.

2c. Convert a regular expression into an equivalent FA.

2d. Construct a regular expression for a regular language.

2e. Convert a context-free grammar into an equivalent pushdown automaton.

2f. Construct a context-free grammar for a given context-free language.

2f. Design an algorithm for a machine model to simulate another model.

2h. Build simple Turing machines.

2i. Prove formally properties of languages or computational models.

2j. Apply a parsing algorithm.

2k. Build a parse tree or a derivation from a context-free grammar.

2l. Use the closure properties in arguments about languages.

**Level 3: Synthesis and Evaluation**

Level 3 outcomes
are those in which the student can apply the material in new
situations. This is the highest level of mastery.

Upon
successful completion of this course, students will be able to:

3a. Compare regular, context-free, recursive, and recursively enumerable languages.

3b. Compare FA, PDA, and Turing machines.

**Textbook:** *Introduction to the Theory of Computation*,
by Michael Sipser (both 2nd and 3rd editions are OK). This book is
available at the bookstore and through major online book retailers,
and you are expected to acquire a copy for your use in this course.
Photocopied textbooks are illegal and their use will not be
tolerated.

**Assignments:** Reading and homework assignments will be
announced on the class website. You should expect to spend at least
10 hours/week outside of class on reading and homework.

**Exams:** There will be three tests: on September 23, October
21, and November 23, and the final exam on December 7, 1-3:45 pm.
The logistics of each test is very straightforward:

- At the class start time, I will email the test to everyone.
- Do not waste time copying the questions, just write your answers on sheets of paper, scan it with your phones and send it back to me. If you are using an iPad or any other device, just send the answers to me. As long as I can read it I am OK.

Similar to homeworks, I will post solution, send you the grades, and answer questions if something is not clear.

As usual, if you are unable to attend the test, let me know, I will organize a different version of the text at a time convenient for you.

**Grading:** Each topic means home assignments (mainly on the
sheets of paper, but some on the real computer). Maximum number of
points:

- first test: 15
- second test: 15
- third test: 15
- home assignments and quizzes: 20
- final exam: 35

The nominal percentage-score-to-letter-grade conversion is as follows:

- 90% or higher is an A
- 80-89% is a B
- 70-79% is a C
- 60-69% is a D
- below 60% is an F

**Homework Assignments:** Each topic means home assignments.
Howeworks will be usually assigned on Tuesday and be due on
Thursday, by the start of the Thursday class. To submit a homework,
send it to the Teaching Assistant (TA) by email. If it is not
electronic, scan it and send him/her the scanned version.
If you have a legitimate reason to be late, let me and the TA know,
you can then submit it until the following Tuesday. If you were
simply late, you can still submit until next Tuesday, but then the
TA will take off points for submitting late.

The TA will take off points for submitting late. He/she will send you the grades. On Tuesday the next week, I will post correct solutions, and both I and the TA will be glad to answer questions if needed.

Since I will be posting correct solutions to homeworks, it does not make any sense to accept very late assignments: once an assignment is posted, it make no sense for you to copy it in your own handwriting, this does not indicate any understanding. So, please try to submit your assignments on time.

Things happen. If there is an emergency situation and you cannot submit it on time, let me know, you will then not be penalized -- and I will come up with a similar but different assignment that you can submit directly to me (not to the TA) when you become available again.

Homework must be done individually. While you may discuss the problem in general terms with other people, your answers and your code should be written and tested by you alone. If you need help, consult the instructor or the TA.

**Quizzes:**
The purpose of a quiz is to ensure that you have read the weekly
reading assignment and to verify that you have mastered the major concepts
of recent lectures. Quizzes typically will be about 5-10 minutes in length and
will cover the material assigned to be read for the upcoming lecture plus
selected concepts from previous lectures.
There will be no make-up on missed quizzes.

**Special Accommodations:** If you have a disability and need
classroom accommodations, please contact the Center for
Accommodations and Support Services (CASS) by email to cass@utep.edu. For additional
information, please visit the CASS website at http://www.sa.utep.edu/cass.
CASS's staff are the only individuals who can validate and if need
be, authorize accommodations for students.

**Scholastic Dishonesty:** Any student who commits an act of
scholastic dishonesty is subject to discipline. Scholastic
dishonesty includes, but not limited to cheating, plagiarism,
collusion, submission for credit of any work or materials that are
attributable to another person.

*Cheating* is:

- copying from the test paper of another student;
- communicating with another student during a test to be taken individually;
- giving or seeking aid from another student during a test to be taken individually;
- possession and/or use of unauthorized materials during tests (i.e. crib notes, class notes, books, etc.);
- substituting for another person to take a test;
- falsifying research data, reports, academic work offered for credit.

- using someone's work in your assignments without the proper citations;
- submitting the same paper or assignment from a different course, without direct permission of instructors.

*Collusion* is unauthorized collaboration with another person
in preparing academic assignments.

Instructors are required to -- and will -- report academic dishonesty and any other violation of the Standards of Conduct to the Dean of Students.

NOTE: When in doubt on any of the above, please contact your instructor to check if you are following authorized procedure.

**Daily Schedule:** (tentative and subject to change)

*August 24:* topics to cover:

- motivations for the class: basis for compiler design; need to detect when a task is not algorithmically solvable; see lecture;
- notion of a finite automaton; see lecture.

*August 26:* topics to cover:

- simple examples of finite automata -- for recognizing integers and for recognizing real numbers; see lecture;
- formal notations for describing a finite automaton; see lecture;
- algorithms for designing a finite automata that recognize union and intersection of regular languages; see lecture.

*August 31:* topics to cover:

- notion of a non-deterministic automaton (NFA);
- how to transform NFAs recognizing two languages into an NFA for their union;
- notion of concatenation of two languages;
- how to transform NFAs recognizing two languages into an NFA for their concatenation;
- the notion of a Kleene star;
- how to transform a NFA recognizing a language into a NFA for recognizing its Kleene star;
- notion of a regular expression;
- how to transform a NFA into a deterministic one;

*September 2:* topics to cover:

- how to transform a finite automaton into a corresponding regular expression; see lecture;
- how to simulate finite automata; see lecture.

*September 7:* topics to cover:

- Pigeonhole Principle; Pumping Lemma; see lecture;
- proof that some languages are not regular; examples of non-regular languages; see lecture.

- notion of a pushdown automaton; examples of pushdown automata; see lecture;
- notion of a context-free grammar; examples of context-free grammars related to programming; examples of context-free grammars that generate non-regular languages; see lecture.

*September 14:* topics to cover:

- how to transform a finite automaton into a context-free grammar; see lecture;
- how to transform a context-free grammar into a (non-deterministic) pushdown automaton; see lecture.

*September 16:* topics to cover:

*September 21:* overview for Test 1.

*September 23:* Test 1.

*September 28:* overview of Test 1 results.

*September 30:* topics to cover:

- Chomsky normal form (cont-d); see lecture;
- transforming a pushdown automaton into a context-free grammar; see lecture.

*October 5:* topics to cover:

- transforming a pushdown automaton into a context-free grammar (cont-d); see lecture;
- how compilers actually work: priority technique; see first part of the lecture.

*October 7:* topic to cover:

- priority techniques beyond simple arithmetic expression; see second part of the lecture.

*October 12:* topic to cover:

- compiling LL(k) languages; see lecture.

*October 14:* topics to cover:

- Pumping Lemma for context-free grammars;
- proof that some languages are not context-free;

*October 19:* preview for Test 2

*October 21:* Test 2

*October 26:* review of Test 2 results

*October 28:* topics to cover:

- main ideas behind Turing machines;
- unary code;
- Turing machines for processing numbers in unary code;
- lowest-bit first vs. highest-bit first computer representation of numbers;
- Turing machines for simple operations with binary numbers;
- how to transform a finite automaton into a Turing machine;

*November 2:* topics to cover:

- how to simulate a Turing machine; see lecture;
- how to represent a Turing machine as a finite automaton with two stacks; see paper.

*November 4:* topics to cover:

- feasible vs. non-feasible algorithms;
- example showing that the current definition of feasibility is not always adequate;

*November 9:* topics to cover:

- a general notion of a problem -- examples, resulting definition of the class NP;
- class P;
- P = NP problem;
- notion of reduction; examples of reduction;
- notion of NP-hardness and NP-completeness;
- examples of NP-hard problems;

*November 11:* topics to cover:

- proof by contradiction: general idea;
- proof that square root of 2 is not a rational number;

*November 16:* topics to cover:

- definition of a halting problem;
- proof that it is not possible to check whether a given program halts on given data;

*November 18:* topics to cover:

- Church-Turing thesis: what is it, is it a mathematical statement, is it a statement about the physical world; see lecture ;
- the notion of a recursive (decidable) language; the notion of a recursively enumerable (Turing-recognizable) language; see lecture.

*November 18:* preview for Test 3

*November 23:* Test 3.

*November 30:* topics to cover:

- overview of Test 3 results;
- Church-Turing thesis: what is it, is it a mathematical statement, is it a statement about the physical world; see lecture ;
- the notion of a recursive (decidable) language; the notion of a recursively enumerable (Turing-recognizable) language; see lecture.

*December 2:* preview for final exam.