1 / 33

Set Theory

Set Theory. Dr. Ahmed Elmoasry. Contents. Ch I: Experiments, Models, and Probabilities. Ch II: Discrete Random Variables Ch III: Discrete Random Variables. Ch I: Experiments, Models, and Probabilities. Set Theory Applying set theory to probability Probability Axioms

fay-glass
Download Presentation

Set Theory

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Set Theory Dr. Ahmed Elmoasry

  2. Contents Ch I: Experiments, Models, and Probabilities. Ch II: Discrete Random Variables Ch III: Discrete Random Variables

  3. Ch I: Experiments, Models, and Probabilities. Set Theory Applying set theory to probability Probability Axioms Some consequences of the Axioms Conditional probability Independence sequential Experiments and tree diagrams Counting Methods Independent trials

  4. Sets • Definition. A Set is any well defined collection of “objects.” • Definition. The elements of a set are the objects in a set. • Notation. Usually we denote sets with upper-case letters, elements with lower-case letters. The following notation is used to show set membership • means that x is a member of the set A • means that x is not a member of the set A.

  5. Ways of Describing Sets • List the elements • Give a verbal description • “A is the set of all integers from 1 to 6, inclusive” • Give a mathematical inclusion rule

  6. Examples of Sets • A={MUJ university, QAS University, the planet Mercury} • B={x2 | x =1,2,3,… } • C={all students who weigh more than 60 kg} • I={all positive integers, negative integers, and 0}

  7. Set Equality • We say that A=B iff B  A and A  B • Or • A={0,17,46} B= {46,0,17} C={17,0,46}

  8. Some Special Sets • The Null Set or Empty Set. This is a set with no elements, often symbolized by • The Universal Set. This is the set of all elements currently under consideration, and is often symbolized by

  9. Membership Relationships • Definition. Subset. “A is a subset of B” We say “A is a subset of B” if , i.e., all the members of A are also members of B. The notation for subset is very similar to the notation for “less than or equal to,” and means, in terms of the sets, “included in or equal to.” S x6 B x1 x2 x3 x5 A x4 x7

  10. Membership Relationships • Definition. Proper Subset. “A is a proper subset of B” We say “A is a proper subset of B” if all the members of A are also members of B, but in addition there exists at least one element c such that but . The notation for subset is very similar to the notation for “less than,” and means, in terms of the sets, “included in but not equal to.”

  11. Combining Sets – Set Union A • “A union B” is the set of all elements that are in A, or B, or both. • This is similar to the logical “or” operator. B

  12. Combining Sets – Set Intersection • “A intersect B” is the set of all elements that are in both A and B. • This is similar to the logical “and”

  13. Ex. Of set union • A is the set of student, who weigh more than 65 kg. • B is the set of student, who tall more than 165 cm. A x3 B x1 x2 x4 x5 x6 x7 x8 x9 x10

  14. Set Complement • “A complement,” or “not A” is the set of all elements not in A. • The complement operator is similar to the logical not, and is reflexive, that is, A

  15. Set Difference • The set difference “A minus B” is the set of elements that are in A, with those that are in B subtracted out. Another way of putting it is, it is the set of elements that are in A, and not in B, so

  16. Examples

  17. Venn Diagrams • Venn Diagrams use topological areas to stand for sets. I’ve done this one for you.

  18. Venn Diagrams • Try this one!

  19. Venn Diagrams • Here is another one

  20. Mutually Exclusive and Exhaustive Sets • Definition. We say that a group of sets is exhaustive of another set if their union is equal to that set. For example, if we say that A and B are exhaustive with respect to C. • Definition. We say that two sets A and B are mutually exclusive if , that is, the sets have no elements in common.

  21. Mutually Exclusive Sets • A and B are disjoint iff A∩ B =  A B

  22. Set Partition • Definition. We say that a group of sets partitions another set if they are mutually exclusive and exhaustive with respect to that set. When we “partition a set,” we break it down into mutually exclusive and exhaustive regions, i.e., regions with no overlap. The Venn diagram below should help you get the picture. In this diagram, the set A (the rectangle) is partitioned into sets W,X, and Y.

  23. Set Partition

  24. De Morgan’s Law

  25. Some Test Questions

  26. Some Test Questions

  27. Some Test Questions

  28. Some Test Questions

  29. Some Test Questions

  30. Some Test Questions

  31. Some Test Questions

  32. Some Test Questions

  33. Some Test Questions

More Related