"acts upstream of" . . _:b1214534 . . _:b1214535 _:b1214534 . "c involved in regulation of p if c enables f and f causally upstream of p" . _:b1214535 . . "A faulty traffic light (material entity) whose malfunctioning (a process) is causally upstream of a traffic collision (a process): the traffic light acts upstream of the collision." . _:b1214534 . _:b1214535 .