I'm learning probability and I've just found this on a book:
The bold $x$ is $x=(x_1,x_2,...,x_n)$.
I'm not sure what this means. I think I have to multiply all of the sums of each element of the bold $x$, like this:
$$\sum_xP(x)=\sum_{x_1}P(x_1)·\sum_{x_2}P(x_1,x_2)·...·\sum_{x_n}P(x_1,x_2,...,x_n)$$
Is that correct?
By the way, I'm trying to calculate the joint probability.
You can find the book I'm using here, page 15.