research article
On the existence of ordinary triangles
Let P be a finite point set in the plane. A \emph{c-ordinary triangle} in P is a subset of P consisting of three non-collinear points such that each of the three lines determined by the three points contains at most c points of P. Motivated by a question of Erd\H{o}s, and answering a question of de Zeeuw, we prove that there exists a constant c>0 such that P contains a c-ordinary triangle, provided that P is not contained in the union of two lines. Furthermore, the number of c-ordinary triangles in P is Ω(|P|).
Type
research article
Author(s)
Mojarrad, Hossein Nassajian
Naszódi, Márton
Solymosi, József
Stich, Sebastian U.
Szedlák, May
Date Issued
2017
Publisher
Published in
Volume
66
Start page
28
End page
31
Editorial or Peer reviewed
REVIEWED
Written at
OTHER
Available on Infoscience
August 2, 2017
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