Common mathematical symbols used in sets

1. {} (braces or curly brackets) - used to denote a set. For example, {1, 2, 3} represents a set containing the elements 1, 2, and 3.
2. ∈ (element of) - used to show that an element belongs to a set. For example, if A = {1, 2, 3}, then 2 ∈ A.
3. ∉ (not an element of) - used to show that an element does not belong to a set. For example, if A = {1, 2, 3}, then 4 ∉ A.
4. ∅ (empty set) - used to represent a set with no elements.
5. ⊆ (subset) - used to show that one set is a subset of another set. For example, if A = {1, 2, 3} and B = {1, 2, 3, 4}, then A ⊆ B.
6. ⊂ (proper subset) - used to show that one set is a proper subset of another set. A proper subset is a subset that is not equal to the original set. For example, if A = {1, 2, 3} and B = {1, 2, 3, 4}, then A ⊂ B.
7. ⊇ (superset) - used to show that one set is a superset of another set. For example, if A = {1, 2, 3} and B = {1, 2}, then A ⊇ B.
8. ⊃ (proper superset) - used to show that one set is a proper superset of another set. A proper superset is a superset that is not equal to the original set. For example, if A = {1, 2, 3} and B = {1, 2}, then A ⊃ B.
9. ∪ (union) - used to show the set of all elements that belong to at least one of two or more sets. For example, if A = {1, 2, 3} and B = {2, 3, 4}, then A ∪ B = {1, 2, 3, 4}.
10. ∩ (intersection) - used to show the set of all elements that belong to all of two or more sets. For example, if A = {1, 2, 3} and B = {2, 3, 4}, then A ∩ B = {2, 3}.
11. \ (set difference) - used to show the set of all elements that belong to one set but not another. For example, if A = {1, 2, 3} and B = {2, 3, 4}, then A \ B = {1}.
12. | (such that) - used to describe a property that the elements of a set must satisfy. For example, {x | x is a positive integer} represents the set of all positive integers.