1. ## question about set partitions

Given the partition P= {124; 5; 36} in a set of 6 elements,
How could you find the number of different partitions of 6 elements into 3 blocks?

What is this question asking me to do?

2. Originally Posted by gammaman
Given the partition P= {124; 5; 36} in a set of 6 elements,
How could you find the number of different partitions of 6 elements into 3 blocks?
Are you saying that $\left\{ {\{ 1,2,4\} ,\{ 5\} ,\{ 3,6\} } \right\}$ is an example of a partition of $\left\{ {1,2,3,4,5,6} \right\}$?

Is this what you are looking for:http://mathworld.wolfram.com/Stirlin...condKind.html?
If so look at equation #7.

3. Yes what is posted is a partition of a set of six elements 1......6.

4. Actually I understand the first part of the question which says, how many ways can you partition a set of six elements. This is just done with a bell number. It is the second part which says "into 3 blocks" that I do not understand. {124; 5; 36} This is three blocks. 124 is a block 5 is a block and 36 is a block. As you questioned, 124 means 1,2,4.

5. Originally Posted by gammaman
Yes what is posted is a partition of a set of six elements 1......6.
Well look at the webpage I gave you.
Scan down to formula (7).