Set Theory

set

a group or collection of objects

elements or members

objects contained in a set

roster method

a set specified by listing the elements and enclosing them in braces

word statement

a set specified by a descriptive sentence

null/empty set

a set with no elements

equal set

sets that contain the exact same elements

matching sets

sets that can be placed in a one-to-one correspondence

subset

Set A is a subset of Set B if everything in Set A is in Set B

union

the single set that has all the elements which are in two (or. more) sets

intersection

the single set contained all those elements which two (or more) sets have in common

number associated

the number of elements in a set

finite set

a set that has a definite number of elements

infinite set

a set that cannot be counted because they are unlimited

disjoint set

sets that do not have anything in common

universal set

the set from which all subsets are selected in a discussion

∅

symbol for null set or empty set

∩

symbol for intersection

∪

symbol for union

∈

symbol for "members of"

∉

symbol for "not a member of "

⊄

symbol for "not a subset of"

c

symbol for "subset of"

U (capital dark U)

symbol for Universal set

{ }

symbol for empty set or null set