Combinatorial Geometry


    • Incidence Structure
      • An incidence structure is a triple (V, B, ∼) so that V, B are disjoint sets and ∼ is a relation on V \times B.
      • We call elements of V points, elements of B blocks or lines and we associate each line with the set of points incident with it.
      • So, if p \in V and b \in B satisfy p ∼ b we say that p is contained in b and write p \in b and if b, b' \in B we let b \cap b' = \{p \in P : p ∼ b, p ∼ b'\}