Discrete Mathematics Overview

Definition of Discrete Mathematics

  • Discrete Mathematics refers to the study of distinct or unconnected elements.

  • It involves the study of mathematical structures that are fundamentally discrete rather than continuous.

Importance of Studying Discrete Mathematics

  • Develops mathematical maturity.

  • Serves as a gateway to more advanced courses in computer science and mathematics.

Module and Set Theory

Introduction to Module and Set Theory

  • Instructor: Aarbaz Alam

  • Focus: Understanding formal definitions and applications of sets.

Module Administration

  • Course Organisation:

    • 13 sessions from Week 1 (Introduction) to Week 12 (Review and Support Session).

    • One online multiple-choice test and one assignment/logbook submission involved.

    • The passing mark for the module is 40%.

Material Content

Set Theory

Basic Definitions
  • Set: An unordered collection of distinct objects, referred to as elements or members of the set.

    • Example Notation:

    • If studenta belongs to Classa, it is denoted as:
      student<em>aClass</em>astudent<em>a ∈ Class</em>a

Properties of Sets
  • Well-defined: The defining characteristic should be clear and specific.

  • Collection: Can contain any number of items (including zero).

  • Cardinality: The number of items in a set is termed the cardinality, denoted by:
    S|S|

  • Distinct: Repetitions are not allowed and order of elements typically does not matter.

  • Homogeneous: All members must be of the same type.

  • Single Entity: Treated as a single variable during computations.

Types of Sets
  1. Null Set: A set with cardinality 0, denoted by the Greek letter phi (ϕ), e.g., ϕ = {}.

  2. Singleton Set: A set with cardinality 1, e.g., S = {a}.

  3. Finite Set: A set with a finite number of elements, e.g., S = {a, b, …, z} |S| = 26.

  4. Countably Infinite Set: An infinite set with a discernible pattern, e.g., S = {2, 4, 6, 8, …}.

  5. Uncountably Infinite Set: An infinite set without a specific pattern.

  6. Crisp Set: A set where elements are easily separable.

Set Representation
  • Venn Diagram:

    • Graphical method to represent sets where overlaps represent common members.

    • Example: Let A be a set of all birds and B be a set of all flying species. Not all flying species are birds (e.g., mosquitoes).

Set Operations
Unary Operations
  • Membership: Notation and examples provided.

    • Example: For a set M = {all mammals}, the complement (not mammals) is denoted as Mᶜ.

  • Complement: ( U ackslash S ) or the set of elements not in S.

Binary Operations
  • Union: X = A  B ; combines elements from both sets A and B.

    • Example: If A = {2, 4, 6} and B = {10, 12, 14}, then A ∪ B = {2, 4, 6, 10, 12, 14}.

  • Intersection: X = A  B ; identifies common elements between A and B.

    • Example: If A = {2, 6, 8, 10} and B = {6, 9, 10, 12}, then A ∩ B = {6, 10}.

  • Disjoint Sets: If A  B = ϕ , then the sets have no common elements.

  • Difference: X=ABX = A - B; set contains members from A that are not in B.

    • Example: If A = {2, 4, 6, 8} and B = {2, 6, 10, 12}, then A - B = {4, 8}.

  • Cartesian Product: X=AimesBX = A imes B; creates all possible ordered pairs.

    • Example with subjects: If A = {Physics, Chemistry, Biology} and B = {History, Geography, Sociology}, combinations yield tuples such as (Physics, History), (Chemistry, Geography), etc.

  • Subsets: A set A is a subset of B (A ⊆ B) if all members of A are in B.

    • Example: A = {all prime numbers}, B = {all whole numbers}.

  • Power Set: The set of all possible subsets of a set S, denoted as P(S).

    • Example: For A = {1, 2, 3}, P(A) = {ϕ, 1, 2, 3, (1,2), (1,3), (2,3), {1,2,3}}.

    • Theorem: P(S)=2S|P(S)| = 2^{|S|}\n

Set Identities
  • Various laws governing set operations, such as:

    • Identity laws,

    • Domination laws,

    • Idempotent laws,

    • Complementation laws,

    • Commutative laws,

    • Distributive laws,

    • De Morgan's laws.

De Morgan's Laws
  1. Law of Union: (AB)c=AcBc(A ∪ B)ᶜ = Aᶜ ∩ Bᶜ

  2. Law of Intersection: (AB)c=AcBc(A ∩ B)ᶜ = Aᶜ ∪ Bᶜ

Contact and Administration

Questions and Support

  • For academic questions, students should:

    1. Raise hands during lectures.

    2. Use the VLE forum for questions.

    3. Email the teaching team using the specified formatting.

Teaching Team Details

  • Module Leader: Aarbaz Alam (alema13@lsbu.ac.uk)

  • Tutors: Aarbaz Alam, Dr. Bugra Alkan, Dr. Louis Spring, Paul Carden, Julie McCarthy, Bisi Bode Kolawole, Louie Webb.

Study Recommendations

  • Study lectures actively.

  • Solve tutorial problems regularly.

  • Review reference materials such as Kenneth H. Rosen's "Discrete Mathematics and Its Applications" (Eighth Edition).

Attendance Guidelines

  • Attend lectures punctually and ensure to sign the attendance sheet multiple times as required.

Reference Material

  • Primary textbook: Kenenth H. Rosen - "Discrete Mathematics and Its Applications" (Eighth Edition).