Talk:Ordered partitions

Incorrect math statement

The task says:

Note that the number of elements in the list is

$({\mathit {arg}}_{1}+{\mathit {arg}}_{2}+...+{\mathit {arg}}_{n}\ \mathrm {choose} \ arg_{1})*({\mathit {arg}}_{2}+{\mathit {arg}}_{3}+...+{\mathit {arg}}_{n}\ \mathrm {choose} \ {\mathit {arg}}_{2})*\ldots *({\mathit {arg}}_{n}\ \mathrm {choose} \ {\mathit {arg}}_{n})$

But this cannot be right.

The task with args 1,2,4 would generate 105 distinct partitions. But 4 choose 1 is 0 and 4 choose 2 is 0 and 4 choose 4 is 1, so the above formula would give a result of 6. --Rdm 22:27, 7 February 2011 (UTC)

Never mind, I fixed it. --Rdm 22:36, 7 February 2011 (UTC)

Is it really fixed? As far as I know choose, the bigger number should be on the left. Anyways, I'll change it to

${{\mathit {arg}}_{1}+{\mathit {arg}}_{2}+...+{\mathit {arg}}_{n} \choose {\mathit {arg}}_{1}}\cdot {{\mathit {arg}}_{2}+{\mathit {arg}}_{3}+...+{\mathit {arg}}_{n} \choose {\mathit {arg}}_{2}}\cdot \ldots \cdot {{\mathit {arg}}_{n} \choose {\mathit {arg}}_{n}}$

to make it clearer --Eugen 10:36, 8 February 2011 (UTC)