I am having a little trouble understanding a multi sigma notation. I have a double sigma notation, the first sigma is directly followed by a second sigma with no arithmetic operator between them. i am given:
S(n) = (First Sigma) (Second Sigma) i
[the "i" is the formula after the second sigma. indexes : first sigma==>lower index :: k=1, upper index=n
second sigma==> lower index:: i=1, upper index=k]
So this seems to be .
Now, use that for any and (you can easily prove both formulae by
induction), and , plus a little algebra to deduce the result they want.
The double notation may be understood as follows: make the first index run, and for each value it takes make the second sum's index run.
i am asked to prove that
(I don't know how to make the sigma signs appear in this forum.)
I am asking if someone can explain to me what the double sigma notation means.
My understanding is this:
I replace the second sigma with a formula, so that the formula preceded by the first sigma is used for the proof .
Is that right?