distribution over x given that observation then a new thing came in for Y and we have a model of how Y acts given X and Z and practice often the Z will disappear here because Y will only depend on X not on Z but in channel YK depend on X and Z and then we can combine that together to know what now new distribution is over state X then another concept that will be very important is conditional independence so conditional independence is a lot like independence but a little less strict independence is a property done and sometimes it's nice