## Oriented matroids and complete-graph embeddings on surfaces

- Jürgen Bokowski, Tomaz Pisanski
- J. Comb. Theory, Ser. A
- 2007

- Published 1998 in Discrete & Computational Geometry
DOI:10.1007/PL00009373

LetA be an arrangement of n pseudolines in the real projective plane and let p3(A) be the number of triangles of A. Grünbaum has proposed the following question. Are there infinitely many simple arrangements of straight lines with p3(A) = 3n(n− 1)? In this paper we answer this question affirmatively.