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Elem. Set Theory
As of mathsisfun.com and efgh.com.
| Term | Definition |
|---|---|
| Set | Collection of items considered as a whole |
| Elements | Items in a set |
| Contained in | ∈ |
| Not contained in | ∉ |
| Null | ∅ |
| Subset | Every item that is in A is in B |
| Such that | | |
| Intersection | The number of elements that two sets have in common, ∩ |
| Proper subset | ⊂ |
| Subset | ⊆ |
| Union | All of the elements that are present, ∪ |
| Disjoint | No elements in common |
| Venn diagram | Sets are represented as the interiors of overlapping circles |
| Minus | - |
| Ordered pair | Two elements in a specified order |
| Cross product | The set of ordered pairs whose first and second elements are part of A and B, respectively |
| Relation | Set of ordered pairs of elements of A |
| Obey relation | ~ |
| Equivalence | Two sets are reflexive, symmetric, and transitive |
| Reflexive | a~a |
| Symmetric | a~b means that b~a |
| Transitive | a~b and b~c means that a~c |
| Partition | Subsets are disjoint and union is A |
| Equivalence classes | The sets in a partition associated with an equivalence relation |