, and by forming the locus of event-particles on rects or point-tracks through
and intersecting
, including also event-particles on the point-track through
and parallel to
. Any matrix can be generated in either of the two ways. Furthermore matrices can be generated by the use of parallels in the same way as levels are generated as explained in [44.1] and as assumed in [43.4].
[45. Null-Tracks]. 45.1 The relations between rects and point-tracks are best understood by taking a rect