Fungrim entry: 92cc17

B_{3} = \# \left\{\left\{\left\{1\right\}, \left\{2\right\}, \left\{3\right\}\right\}, \left\{\left\{1\right\}, \left\{2, 3\right\}\right\}, \left\{\left\{2\right\}, \left\{1, 3\right\}\right\}, \left\{\left\{3\right\}, \left\{1, 2\right\}\right\}, \left\{\left\{1, 2, 3\right\}\right\}\right\} = 5

Definitions:

Fungrim symbol	Notation	Short description
`BellNumber`	$B_{n}$	Bell number
`Cardinality`	$\# S$	Set cardinality

Source code for this entry:

Entry(ID("92cc17"),
    Equal(BellNumber(3), Cardinality(Set(Set(Set(1), Set(2), Set(3)), Set(Set(1), Set(2, 3)), Set(Set(2), Set(1, 3)), Set(Set(3), Set(1, 2)), Set(Set(1, 2, 3)))), 5))

Topics using this entry

Bell numbers

Copyright (C) Fredrik Johansson and contributors. Fungrim is provided under the MIT license. The source code is on GitHub.

2021-03-15 19:12:00.328586 UTC