enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Bell number - Wikipedia

    en.wikipedia.org/wiki/Bell_number

    Partitions of sets can be arranged in a partial order, showing that each partition of a set of size n "uses" one of the partitions of a set of size n − 1. 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 ...

  3. Partition of a set - Wikipedia

    en.wikipedia.org/wiki/Partition_of_a_set

    Partitions of a 4-element set ordered by refinement. A partition α of a set X is a refinement of a partition ρ of X—and we say that α is finer than ρ and that ρ is coarser than α—if every element of α is a subset of some element of ρ. Informally, this means that α is a further fragmentation of ρ. In that case, it is written that ...

  4. Cartesian product - Wikipedia

    en.wikipedia.org/wiki/Cartesian_product

    An illustrative example is the standard 52-card deck. 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 ...

  5. Bell triangle - Wikipedia

    en.wikipedia.org/wiki/Bell_triangle

    The remaining partitions of these four elements either do not have 3 in a set by itself, or they have a larger singleton set {4}, and in either case are not counted in A 3,2. In the same notation, Sun & Wu (2011) augment the triangle with another diagonal to the left of its other values, of the numbers

  6. Stirling numbers of the second kind - Wikipedia

    en.wikipedia.org/wiki/Stirling_numbers_of_the...

    An r-associated Stirling number of the second kind is the number of ways to partition a set of n objects into k subsets, with each subset containing at least r elements. [17] It is denoted by S r ( n , k ) {\displaystyle S_{r}(n,k)} and obeys the recurrence relation

  7. Partition algebra - Wikipedia

    en.wikipedia.org/wiki/Partition_algebra

    The partition algebra is an associative algebra with a basis of set-partition diagrams and multiplication given by diagram concatenation. [1] Its subalgebras include diagram algebras such as the Brauer algebra, the Temperley–Lieb algebra, or the group algebra of the symmetric group. Representations of the partition algebra are built from sets ...

  8. Ramanujan's congruences - Wikipedia

    en.wikipedia.org/wiki/Ramanujan's_congruences

    In mathematics, Ramanujan's congruences are the congruences for the partition function p(n) discovered by Srinivasa Ramanujan: (+) (), (+) (), (+) ().In plain words, e.g., the first congruence means that If a number is 4 more than a multiple of 5, i.e. it is in the sequence

  9. Product (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Product_(mathematics)

    In set theory, a Cartesian product is a mathematical operation which returns a set (or product set) from multiple sets. That is, for sets A and B, the Cartesian product A × B is the set of all ordered pairs (a, b) —where a ∈ A and b ∈ B. [5] The class of all things (of a given type) that have Cartesian products is called a Cartesian ...