Hi guys,

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. Tonio
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?

Need help.

Thanks.