All Questions
18
questions
4
votes
1
answer
2k
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Confused between cyclic sum and symmetric sums.
four variables $a, b, c, d$ are given, what is the symmetric and cyclic sum?
I thought:
$$\sum_{cyc} ab = ab + ac + ad + bc + bd + cd$$
And
$$\sum_{sym} ab = 2(ab + ac + ad + bc + bd + ...
- 11.3k
13
votes
1
answer
2k
views
Notation: What is the scope of a sum?
I would interpret $\sum_{i=1}^2 x_i + y$ as $x_1 + x_2 + y$, but I would interpret $\sum_{i=1}^2 x_i + y_i$ as $x_1 + y_1 + x_2 + y_2$. I realize this is a little inconsistent. Should the latter be ...
- 233
3
votes
2
answers
206
views
Elementary question on Sums notation
I reading on Sums and I am reading about the difference between using a generalized Sigma notation and the delimited form. Ok, I understand that the generalized form is more expressive.
But I ...
- 359