sum out over these variables is their way to rearrange this into smaller calculations we're going to first multiply everything together and then finally get to some out but we can do smaller bite-sized calculations where we sum some variables out make them disappear and that way not have this exponential blow-up as the thing becomes bigger if you do it naively this way this summation that the variables are binary let's say then there will be two to the horizon number of terms in this summation but by bringing them in in the