@misc{Florek_Jan_On_2011,
 author={Florek, Jan},
 year={2011},
 rights={Wszystkie prawa zastrzeżone (Copyright)},
 publisher={Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu},
 description={Mathematical Economics, 2011, Nr 7 (14), s. 65-70},
 language={eng},
 abstract={Let p, q, rbe any three lines in the plane passing through a common point and suppose that O, P, Q, Rare any four collinear points such that P∈ p, Q ∈ q, R ∈ r, Pand Rare harmonic conjugates with respect to Oand Q(that is, │OP│/ │PQ│= │OR│/│QR│). For every k ≥2, we construct a set Xnof n= 4kpoints, which is distributed on the lines p, q, r, but each element of Xnᵕ\{O\} is incident to at most n/2 lines spanned by Xnᵕ\{O\}.},
 title={On some extremal problem in discrete geometry},
 type={artykuł},
 keywords={Dirac-Motzkin conjecture, Desargues' theorem},
}