Sets
Writing A = {1, 2, 3, 4 } means that the elements of the set A are the numbers 1, 2, 3 and 4. Sets of elements of A, for example {1, 2}, are subsets of A.
Sets can themselves be elements. For example consider the set B = {1, 2, {3, 4}}. The elements of B are not 1, 2, 3, and 4. Rather, there are only three elements of B, namely the numbers 1 and 2, and the set {3, 4}.
The elements of a set can be anything. For example, C = { red, green, blue }, is the set whose elements are the colors red, green and blue.
Read more about this topic: Element (mathematics)
Famous quotes containing the word sets:
“And weren’t there special cemetery flowers,
That, once grief sets to growing, grief may rest:
The flowers will go on with grief awhile,
And no one seem neglecting or neglected?
A prudent grief will not despise such aids.”
—Robert Frost (1874–1963)
“In the beautiful, man sets himself up as the standard of perfection; in select cases he worships himself in it.... Man believes that the world itself is filled with beauty—he forgets that it is he who has created it. He alone has bestowed beauty upon the world—alas! only a very human, an all too human, beauty.”
—Friedrich Nietzsche (1844–1900)
“bars of that strange speech
In which each sound sets out to seek each other,
Murders its own father, marries its own mother,
And ends as one grand transcendental vowel.”
—Randall Jarrell (1914–1965)