So the formula forces us to set every variable except for X1 to false, and now the way that this formula is structured, of course, we could also have chosen to set X2 to true, but then if X2 is set to true, we have this here, so X2 here is 1, 1, 1, 1, which means in order to get these here to go to 1, so we need to have these here go to 1, because this here evaluates to 0, 0, 0, 0, 0, so we have to set all of these variables here to false. 