deleted by some assumption is just the notation beol XT minus 1 by definition means XT minus 1 given all this is just a shorthand notation so for the second-to-last equation or like the third line from the bottom and the second line it goes UT at the last one and then it's CT minus one what happened there like on the conditioning oh ok the only thing that happened there essentially that the UT was removed yeah it's not fully spelled out but essentially UT does not play a role for XT minus 1 because it comes after and so