Related pagesDual incidence structure
Given a line l, the set
is the point row of the line l. Similarly, given a point p, the line pencil through p is defined to be
Note that a line l is not determined by its point row, but this is true in all incidence structures which are usually considered, for example in partial linear spaces.
The concept of an incidence structure is not really usefull for its own sake. It is used as a general setting to define more specific geometric structures.