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 Curious
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Mar
20
accepted What are the initial conditions for the Associated Stirling numbers of the second kind?
Mar
20
comment What are the initial conditions for the Associated Stirling numbers of the second kind?
But then shouldn't S_2(2, 1) == 1 ?
Mar
20
comment What are the initial conditions for the Associated Stirling numbers of the second kind?
What about for n or k < 0? The recurrence allows for this situation as N is reduced by R
Mar
20
asked What are the initial conditions for the Associated Stirling numbers of the second kind?
Mar
20
comment How many ways are there to divide elements into equal unlabelled sets?
Thanks! Is there a way to generalize this such that: if I make D draws with replacement from N distinct items. how many ways are there to get C copies of any K distinct items. I tried to generalize with your analogy of "filling" in the bracket. But for D > C*K it's unclear how to no double count groups.
Mar
20
accepted How many ways are there to divide elements into equal unlabelled sets?
Mar
13
awarded  Curious
Mar
12
awarded  Commentator
Mar
12
comment How many ways are there to divide elements into equal unlabelled sets?
Awesome :), is there a more compact formula that avoids the product?
Mar
12
comment How many ways are there to divide elements into equal unlabelled sets?
Ah, so I should divide by the number of ways of ordering the sets = K!
Mar
12
comment How many ways are there to divide elements into equal unlabelled sets?
Added. I'm concerned that I'm assuming some kind of ordering. @jameselmore
Mar
12
revised How many ways are there to divide elements into equal unlabelled sets?
Added thoughts so far.
Mar
12
asked How many ways are there to divide elements into equal unlabelled sets?
Feb
26
accepted Code that minimizes the variance of sum of weighted random variables?
Feb
26
comment Code that minimizes the variance of sum of weighted random variables?
I can't see to create a dataset for X and Y that give weights that aren't w1=0,w2=1 or w1=1,w2=0? Do you have a simple example?
Feb
26
comment Code that minimizes the variance of sum of weighted random variables?
That's interesting thanks, given that we enforce (w1+w2=1) and w1,w2≥0 surely we would always use the sum of variables that gave weight 1 to the variable with smaller variance and 0 to the one with larger variance?
Feb
25
asked Code that minimizes the variance of sum of weighted random variables?
Feb
21
revised How do I count number of ways of drawing items with certain number of duplicates?
added 207 characters in body
Feb
21
comment How do I count number of ways of drawing items with certain number of duplicates?
@user314 I'll edit my post with an example.
Feb
21
asked How do I count number of ways of drawing items with certain number of duplicates?