get a measurement we're multiplying the likelihood of the measurement and then we were renormalize and if our distribution for XT and we can keep tracking over time all right the mark of the assumption makes this even slightly simpler notation and we're good to go all right so and then the last thing here is just the notation the book uses BL belief of XT minus 1 is a shorthand where there's no there's no assumption here it's not like we can delete all this stuff here just to be clear this stuff is now being