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4 votes
2 answers
1k views

$F(n)$ is number of ways to partition set of $n$ without singleton blocks. Prove that $B(n) = F(n) + F(n+1)$

In this case $B(n)$ is $n$-th Bell number. To be honest, I would really love to know if there is a combinatorial proof for that. If there is not, other proofs are appreciated too.
math-traveler's user avatar
1 vote
1 answer
202 views

Constructing a bijection to show that the number of equivalence relations on a finite set is equal to the bell numbers.

It is said that the Bell numbers count the number of partitions of a finite set. How can we prove that what they count is actually the number of partitions? I don't want to take it as a definition; I ...
user821980's user avatar
3 votes
1 answer
292 views

Combinatorial proof for Touchard's congruence

Bell number denoted $B_n$ is the number of ways to partition a set with cardinality $n$ into $k$ indistinguishable sets , where $0\le k\le n$ It's known that Bell numbers obey Touchard's Congruence ...
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0 votes
2 answers
1k views

Partitions of a set with n elements (proof)

I was reading a textbook about combinatorial mathematic which claimed that we can calculate the exact possible partitions of a set with n elements . I searched it on wikipedia and I read about bell ...
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