# Mathematical Symbols (Part 3)

 Symbol Name Explanation { , } keys the set of…Ex: {a, b, c} represents the set composed of a, b and c. {} or empty set It means that the set has no elements, it is an empty set.Ex:A = {1,2,3}B = {4,5,6}THE B = for all It means "For all" or "For whatever".Ex: x> 0, x is positive. It means that for any x greater than 0, x is positive. belongs Indicates relevance relationship.Ex: 5 N. It means that 5 belongs to the natural numbers. does not belong Does not belong .Ex: -1 N. Means that the number -1 does not belong to the natural numbers. exist Indicates existence.Ex: x Z | x> 3 It means that there is an x ​​belonging to the set of integers such that x is greater than 3. is contained Ex: N Z, that is, the set of natural numbers is contained in the set of integers. not contained Ex: R N, that is, the set of real numbers is not contained in the set of natural numbers. contains Ex: Z N, that is, the set of integers contains the set of natural numbers. if then if thenQ: Jose goes to the marketQ: Jose is going shoppingPwhatIf Joseph goes to the market then he goes shopping. if and only if if and only ifEx:Q: Maria goes to the beachQ: Maria will get good gradesPwhatMaria goes to the beach if and only if she gets good grades. THE B union of sets Reads as "The Union B"Ex:A = {5,7,10}B = {3,6,7,8}THE B = {3,5,6,7,8,10} THE B set intersection Reads as "A Intersection B"Ex:A = {1,3,5,7,8,10}B = {2,3,6,7,8}THE B = {3,7,8} A - B sets difference It is read as "difference from A to B".Is the set of all elements that belong to set A and not belong to set B.Ex: A-B = {X | xThe ex B}