Math 114  Discrete Mathematics

Spring 2018
Prof. D Joyce
Department of Mathematics and Computer Science
Clark University

Clark University
Please bookmark this page, http://math.clarku.edu/~djoyce/ma114/, so you can readily access it.

Course information

Syllabus. Not all of these topics will be covered in the same depth, and homework will not be assigned from all sections.

1 The Foundations: Logic and Proofs

Topics in chapter 1: proposition, truth value, negation, logical operators, compound proposition, truth table, disjuction, conjunction, exclusive or, implication, converse, contrapositive, bit, Boolean variable, bit operation, bit string, bitwise operation; tautology, contradiction, contingency, logical equivalnce, propsitional function De Morgan's laws; predicates, existential quantifier, universal quantifier; nested quantifiers, free & bound variables; rules of inference; theorem, conjecture, proof, lemma, corollary, fallacy, circular reasoning (begging the question), vacuous & trivial proof, direct & indirect proof; proof by cases, counterexample.

2 Basic Structures: Sets, Functions, Sequences, and Summations

Topics in chapter 2: set, axiom, paradox, element, empty set, set equality, subset, finite & infinite set, cardinality, power set,products of sets; union, intersection, disjoint sets, set difference, set complement, symmetric difference, Venn diagrams; function, domain, codomain, image, preimage, range, onto function, 1-1 function, 1-1 correspondence, inverse function, composition, floor, ceiling; sequence, string, summation notation, product notation.

3 The Fundamentals: Algorithms, the Integers, and Matrices

Topics in chapter 3: algorithm, searching algorithm, linear search algorithm, binary search algorithm, time complexity, space complexity, worst-case time complexity, average-case time complexity; divisibility, prime & composite number, Mersenne prime, greatest common divisor, relatively prime, pairwise relatively prime integers, least common multiple, remainder & modulus, encryption & decryption, binary representation, hexadecimal represention, linear combination, inverse modulo n, linear congruence, pseudoprime, private and public key encryption; Euclidean algorithm.

4 Induction, and Recursion

Topics in chapter 4: mathematical induction; recursive defined functions, sets, and structures; recursive algorithms; iteration.

5 Counting

Topics in chapter 5: multiplicative and additive priciples of counting, principle of inclusion and exclusion, tree diagrams; basic and generalized pigeonhole principle; permutatations, r-permutations, combinations; binomial coefficients, Pascal's triangle.

6 Discrete Probability

Topics in chapter 6: foundations of probability, frequency interpretation, symmetric situations, outcomes, events, sample space, sum rule, principle of inclusion and exclusion; uniform distribution, conditional probability, indepencence, Bernoulli trials, binomial distribution; definition of expected value, frequency interpretation, random variables, linearity of expectation, indepedent random variables, variance.

8 Relations

Topics in chapter 8: binary relation, n-ary relation, symmetry, antisymmetry, reflexivity, transitivity, composition; graphs and relations, incidence matrices; closure of a relation, transitive closure; equivalence relation, equivalance class, partition; partial ordering, lexicographic order, Hasse diagrams.

9 Graphs

Topics in chapter 9: definition of graphs, vertices (nodes), edges, directed and undirected graphs, applications of graphs; adjacency of vertices, degree (valence), isolated and pendant vertices, the handshaking theorem, complete graphs, cycles, bipartite graphs, local area networks, subgraphs.

Class notes, quizzes, tests, homework assignments All future dates are tentative. Sections will frequently overflow into the preceding or succeeding days. Furthermore, each section will be discussed on more than one day—on one day when it's introduced, later when there are questions on it and its assignment exercises.

  1. Wednesday, Jan. 17
    Welcome! Discussion of the course.
    Discuss § 1.1. Introduction to symbolic logic of propositions. Concepts of proposition, truth value, compound proposition, logical operator, truth table, negation, conjunction, disjunction (inclusive and exclusive)
  2. Friday, Jan. 19
    Continue discussion of symbolic logic. Concepts of conditional statement (implication), converse, contrapositive, inverse, precedence conventions of logical operators.
  3. Monday, Jan. 22
    § 1.1. Exercises due: 1-4, 7, 10, 15, 16, 19, 21.
    Finish § 1.1, begin § 1.2. Propositional equivalences.
  4. Wednesday, Jan 24
    § 1.1. Exercises due: 23, 31a-d, 32ace, 54, 62. Answers
    Continue § 1.2. Concepts of tautology, contradiction, contingency, logical equivalence, laws such as De Morgan's laws and distributive laws
  5. Friday, Jan 26
    Discuss § 1.3. Predicates and quantifiers. Concepts of predicate (propositional function), universal and existential quantifier. Logical equivalence of propositions involving quantifiers.
  6. Monday, Jan. 29
    § 1.2. Exercises due: 1, 2, 5-7, 12, 14, 17, 20, 27, 35, 46, 48, 50. Answers
    Continue § 1.3., Concepts of counterexample, negation and duality for quantified expressions.
    Begin § 1.4 on nested quantifiers. Concepts of scope of a quantifier, double universal quantifiers, double existential quantifiers, mixed quantifiers.
  7. Wednesday, Jan 31
    Finish § 1.4: negating nested quantifiers.
    Begin § 1.5. Rules of inference. Concepts of proof, validity, rule of inference, specific rules of inference for propositional logic including modus ponens (the law of detachment), modus tollens, hypothetical syllogism, disjunctive syllogism, conjunction, resolution, etc.
  8. Friday, Feb 2
    § 1.3. Exercises due: 1-3, 6, 10, 15-16, 35-36, 52-53. Answers
    More on § 1.5. Rules of inference for predicate logic: universal instantiation and generalization, existential instantiation and generalization.
    Begin § 1.6. Introduction to proofs in mathematics. Theorems, lemmas, and corollaries.
  9. Monday, Feb 5
    § 1.4. Exercises due: 4-6, 12-13, 19-20, 23, 27-28, 31-32, 45-46. Answers
    Continue § 1.6. Direct proofs, contrapositives, proofs of universal theorems, vacuous proofs, proof by contradiction, proofs of equivalence, counterexamples.
  10. Wednesday, Feb 7
    § 1.5. Exercises due: 1-4, 7-8, 9abc, 10abc, 15, 23. Answers
    Discuss § 1.7. Proof methods and strategy. Proof by cases. Existence proofs and nonconstructive existence proofs. Uniqueness proofs. Forward and backward reasoning. The discovery process. Conjectures.
  11. Friday, Feb 9
    § 1.6. Exercises due: 3, 6, 10-11, 39. Answers
    Quiz on sections 1.4 and 1.5. Answers
    Begin Chapter 2. Discuss § 2.1 on sets. Connection to logic. Examples.
  12. Monday, Feb 12
    § 1.7. Exercises due: 3, 12, 21-22. Answers
    Continue § 1.1. Venn diagrams, cardinality, infinite sets, power sets, Cartesian products of sets
    Discuss § 2.2. Operations on sets. Union, intersection, etc., and identities relating to them
    Notes on sets
  13. Wednesday, Feb 14
    § 2.1. Exercises due: 1-2, 17, 26, 27, 29. Answers
    Discuss § 2.3 on functions. One-to-one function (injection), onto function (surjection), one-to-one correspondence (bijection).
  14. Friday, Feb 16
    § 2.2. Exercises due: 1-4, 6-7, 16, 23, 27. 30, 32, 35-36, 38b, 40. Answers
    From § 2.3. Composition and inverse functions. Graphs of functions.
    Discuss § 2.4. Sequences, strings, summation notation, geometric series, product notation.
  15. Monday, Feb 19
    § 2.3. Exercises due: 1-5, 8-11, 19, 28-29, 32, 36, 38, 61a. Answers
    Class cancelled
  16. Wednesday, Feb 21
    Review for the first midterm
  17. Friday, Feb 23
    First midterm on chapter 1 and chapter 2 through § 2.3. You may bring a calculator and a sheet of notes.
    Two versions: First, answers; Second, answers
  18. Monday, Feb 26
    § 3.1 Algorithms. Searching algorithms, sorting algorithms, the halting problem
  19. Wednesday, Feb 28
    § 3.2 The Growth of Functions. Big-O, big omega, big theta notations.
    Growth of functions.
    § 3.3 Complexity of Algorithms. Time complexity, worst case, average case
  20. Friday, March 2
    § 3.1. Exercises due: 2, 11, 12, 16, 19. Answers
    § 3.4 The Integers and Division. Divisibility, modular arithmetic, congruence.

    Spring break, March 5 through March 9.

  21. Monday, March 12
    § 3.2. Exercises due: 1-2, 8-9, 19-20, and § 3.3: 5, 7-9. Answers for 3.2, Answers for 3.3
    § 3.5 Primes and Greatest Common Divisors. Fundamental theorem of arithmetic, Euclid's proof of the infinity of primes, Mersenne primes and perfect numbers, the prime number theorem, greatest common divisor (GCD) and least common multiple (LCM), relatively prime numbers
  22. Wednesday, March 14
    § 3.4. Exercises due: 1-2, 6-7, 9a-d, 11, 16, 33, and § 3.5: 3-5, 14, 20, 22. Answers for 3.4, Answers for 3.5
    § 3.6 Integers and Algorithms: Base conversion, Efficient algorithm for computing powers, the Euclidean algorithm, the extended Euclidean algorithm, solving single linear congruences.
    Cryptography and the number theory behind it
  23. Friday, March 16
    § 3.6. Exercises due: 1-5, 8, 23-24. Answers
    § 4.1: Mathematical induction. Base case, inductive step, inductive hypothesis
  24. Monday, March 19.
    § 3.7. Exercises optional: 1abc, 2abc, 6-7, 18-19, 46. Answers
    More on mathematical induction.
  25. Wednesday, March 21
    § 4.1. Exercises due: 9, 10, 14, 16, 21. Answers
    § 4.2: strong induction and well-ordering
  26. Friday, March 23
    Quiz on §§ 3.2 and 3.5. Answers
    Notes on Combinatorics
    § 5.1. Basic principles of combinatorics. Multiplicative and additive priciples of counting, principle of inclusion and exclusion, tree diagrams. Permutations
  27. Monday, March 26
    § 5.2. The Pigeonhole Principle, generalized pigeonhole principle
    § 5.3. Permutations and Combinations. r-permutations, combinations
  28. Wednesday, March 28
    § 5.4. Binomial Coefficients. Pascal's triangle
    Introduction to discrete probability.
  29. Friday, March 30
    § 5.1. Exercises due: 7-8, 10-12, 16, 23-24, 31, 39, 42. Answers.
    § 5.2. Exercises due: 1-2, 6, 20-21, 30. Answers.
    § 6.1. Basic principles of probability. Uniform finite probability.
  30. Monday, April 2
    § 5.3. Exercises due: 1-2, 6, 8, 10, 15, 20ab, 27-28. Answers.
    § 5.4. Exercises due: 2, 4, 12, 31. Answers.
    § 6.2. Probability theory. Conditional probability, independence.
  31. Wednesday, April 4
    More on § 6.2. Bernoulli trials, binomial distribution, random variables.
    § 6.3. Bayes' theorem.
  32. Friday, April 6
    Review for second midterm on chapters 3 through 5
  33. Monday, April 9
    Second midterm on chapters 3 through 5. You may bring a calculator and a sheet of notes. Answers
  34. Wednesday, April 11
    § 6.1. Exercises due: 3, 5, 6, 10-12, 25, 30. Answers.
    § 6.4. Expected value.
  35. Friday, April 13
    § 6.2. Exercises due: 7, 8, 12, 17, 25, 26, 28. Answers.
    Properties of expected value.
  36. Monday, April 16
    § 6.4. Exercises due: 1-6, 12, 16. Answers.
    § 8.1. Relations. Binary relation on a set S as a subset of S2, functions as relations. Properties of relations: reflexive, symmetric, transitive, antisymmetric. Operations on relations: union, intersection, difference, composition.
    § 8.3. Representing a relation as a matrix and as a directed graph (digraph).
  37. Wednesday, Apr 18
    § 8.5. Equivalence relations, equivalence classes, partitions.
  38. Friday, Apr 20
    § 8.1. Exercises due: 4, 10, 17, 24. Answers.
    § 8.3. Exercises due: 1-2, 5-6, 11-12, 18-19, 31-32. Answers.
    § 5.6. Partial orderings (posets), lexicographic order, Hasse diagrams.
  39. Monday, Apr 23
    § 9.1 Graphs and Graph Models. Vertices and edges, loops, labels. Simple graphs vs. multigraphs. Directed graphs (digraphs) vs. undirected graphs. Graph models, i.e., applications.
  40. Wednesday, Apr 25
    § 8.5. Exercises due: 1-3, 21-23, 26-28. Answers.
    § 8.6. Exercises due: 7, 9-11, 15, 22. Answers.
    § 9.2. Graph terminology and special types of graphs. Adjacency, degree of a vertex, handshaking theorem
  41. Friday, Apr 27. Exercises on graph theory.
  42. Monday, Apr 30. Review.
  43. Thursday, May 3. Alternate final exam, 1:30-3:30
    You may bring a sheet of notes and a calculator to the final.
  44. Monday, May 7. Scheduled final exam, 1:30-3:30 BP 316

Past tests

This page is located on the web at
http://aleph0.clarku.edu/~djoyce/ma114/
David E. Joyce