Search results
Results From The WOW.Com Content Network
Python has built-in set and frozenset types since 2.4, and since Python 3.0 and 2.7, supports non-empty set literals using a curly-bracket syntax, e.g.: {x, y, z}; empty sets must be created using set(), because Python uses {} to represent the empty dictionary.
A set of polygons in an Euler diagram This set equals the one depicted above since both have the very same elements.. In mathematics, a set is a collection of different [1] things; [2] [3] [4] these things are called elements or members of the set and are typically mathematical objects of any kind: numbers, symbols, points in space, lines, other geometrical shapes, variables, or even other ...
The standard playing card ranks {A, K, Q, J, 10, 9, 8, 7, 6, 5, 4, 3, 2} form a 13-element set. The card suits {♠, ♥ , ♦ , ♣ } form a four-element set. The Cartesian product of these sets returns a 52-element set consisting of 52 ordered pairs , which correspond to all 52 possible playing cards.
The cardinality of a set X is essentially a measure of the number of elements of the set. [1] Equinumerosity has the characteristic properties of an equivalence relation (reflexivity, symmetry, and transitivity): [1] Reflexivity Given a set A, the identity function on A is a bijection from A to itself, showing that every set A is equinumerous ...
The total number of partitions of an n-element set is the Bell number B n. The first several Bell numbers are B 0 = 1, B 1 = 1, B 2 = 2, B 3 = 5, B 4 = 15, B 5 = 52, and B 6 = 203 (sequence A000110 in the OEIS). Bell numbers satisfy the recursion + = = and have the exponential generating function
In the Lehmer code for a permutation σ, the number d n represents the choice made for the first term σ 1, the number d n−1 represents the choice made for the second term σ 2 among the remaining n − 1 elements of the set, and so forth. More precisely, each d n+1−i gives the number of remaining elements strictly less than the term σ i.
Sets can themselves be elements. For example, consider the set = {,, {,}}. 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 {,}. The elements of a set can be anything. For example the elements of the set = {,,} are the color red, the number 12, and the set B.
The 52 partitions of a set with 5 elements. In general, is the number of partitions of a set of size . A partition of a set is defined as a family of nonempty, pairwise disjoint subsets of whose union is .