MJ

"Identifying equivalent and equal sets"

Introduction to Sets

  • A set is a collection of distinct objects, considered as an object in its own right.

Key Concepts

  • Equal Sets: Two sets are equal if they contain the exact same elements, regardless of order.
  • Equivalent Sets: Two sets are equivalent if they contain the same number of elements but do not necessarily have to contain the same items.

Main Ideas

  • Sets can be classified as:
    • Equal Sets: If Set A = {1, 2, 3} and Set B = {3, 2, 1}, then Set A is equal to Set B (A = B).
    • Equivalent Sets: If Set C = {1, 2} and Set D = {4, 5}, then Sets C and D are equivalent because they each contain 2 elements (C ≈ D).

Pair of Sets Evaluation

Set Evaluations

  1. Example (a):

    • Set A: Odd numbers between 6 and 14.
    • Set B: Integers between 6 and 14.
    • Conclusion: Sets A and B are equivalent but not equal because they contain the same number of elements but not the same actual elements.
  2. Example (b):

    • Set A: Integers between 4 and 9.
    • Set B: Defined but unspecified.
    • Conclusion: Sets A and B are neither equivalent nor equal due to differing number of elements.
  3. Example (c):

    • Two sets with the same elements: Set A = {7, 9, 11, 13} and Set B = {7, 9, 11, 13}.
    • Conclusion: Both sets contain the exact same elements, so they are both equivalent and equal.
  4. Example (d):

    • Set A contains 4 elements, described as {21, 22, 23, 24}.
    • Set B also described but must be checked; order is irrelevant for equality.
    • Conclusion: Sets A and B are equivalent but not equal as they share the same count but not identical elements.

Definitions According to Examples

  • Equal Sets: When Set A has elements {x} identical to Set B.
  • Equivalent Sets: When Set A has some elements x and Set B has elements y accounting for count only.

Important Notes

  • Equal sets imply equivalency, but equivalency does not imply equality.
  • Order of elements within sets does not affect equality, however, it is essential to count elements for equivalency.

Conclusion

  • Understanding the distinction between equivalent and equal sets is critical for grasping set theory and its applications in mathematics.