a) Let a region of the t − x plane be bounded by the lines t = 0, t = 1, x = 0, x = 1. Within the t − x plane, find the unit outward normal one-forms and their associated vectors for each of the boundary lines?
(b) Let another region be bounded by the straight lines joining the events whose coordinates are (1, 0), (1, 1), and (2, 1). Find an outward normal for the null boundary and find its associated vector?