Example Proof in Set Theory

Description

Senior Freshman Mathematics Mind Map on Example Proof in Set Theory, created by Luke Byrne on 22/04/2018.
Luke Byrne
Mind Map by Luke Byrne, updated more than 1 year ago
Luke Byrne
Created by Luke Byrne about 7 years ago
4
0
1 2 3 4 5 (0)

Resource summary

Example Proof in Set Theory
  1. Proposition: "∀A, B sets, (A ∩ B) ∪ (A\B) = A".
    1. Show (A ∩ B) ∪ (A\B) ⊆ A
      1. ∀x ∈ (A ∩ B) ∪ (A\B), x ∈ (A ∩ B) or x ∈ A\B
        1. If x ∈ (A∩B), then clearly x ∈ A as A∩B ⊆ by definition.
          1. If x ∈ A\B, then by definition, x ∈ A and x !∈ B, so definitely x ∈ A.
            1. In both cases, x ∈ A as needed.
      2. Show A ⊆ (A ∩ B) ∪ (A\B)
        1. Either...
          1. x ∈ B
            1. ... then x ∈ A and x ∈ B, so x ∈ A ∩ B
              1. ... in both cases
                1. x ∈ (A ∩ B) or x ∩ (A\B)
                  1. so x ∈ (A ∩ B) ∪ (A\B), as needed
            2. x !∈ B
              1. x ∈ A and x !∈ B, so x ∈ A\B
          2. Q.E.D.
          Show full summary Hide full summary

          0 comments

          There are no comments, be the first and leave one below:

          Similar

          How to improve your SAT math score
          Brad Hegarty
          GCSE Maths: Pythagoras theorem
          Landon Valencia
          Edexcel GCSE Maths Specification - Algebra
          Charlie Turner
          Mathematics
          Corey Lance
          Graph Theory
          Will Rickard
          Projectiles
          Alex Burden
          Brain Teasers
          Andrea Pan
          MODE, MEDIAN, MEAN, AND RANGE
          Elliot O'Leary
          CUMULATIVE FREQUENCY DIAGRAMS
          Elliot O'Leary
          STEM AND LEAF DIAGRAMS
          Elliot O'Leary