De Bruijn–Erdős theorem (incidence geometry)
In incidence geometry, the De Bruijn–Erdős theorem, originally published by Nicolaas Govert de Bruijn and Paul Erdős , states a lower bound on the number of lines determined by n points in a projective plane. By duality, this is also a bound on the number of intersection points determined by a configuration of lines. Although the proof given by De Bruijn and Erdős is combinatorial, De Bruijn and Erdős noted in their paper that the analogous (Euclidean) result is a consequence of the Sylvester–Gallai theorem, by an induction on the number of points.
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Combinatorial designDe BruijnDe Bruijn-Erdos theorem (incidence geometry)De Bruijn-Erdős theorem (incidence geometry)De Bruijn–Erdos theorem (incidence geometry)De Bruijn–Erdős theoremErdősFisher's inequalityIncidence geometryLinear space (geometry)List of theoremsList of things named after Paul ErdősNicolaas Govert de BruijnPartial linear spaceProofs from THE BOOKSylvester–Gallai theorem
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De Bruijn–Erdős theorem (incidence geometry)
In incidence geometry, the De Bruijn–Erdős theorem, originally published by Nicolaas Govert de Bruijn and Paul Erdős , states a lower bound on the number of lines determined by n points in a projective plane. By duality, this is also a bound on the number of intersection points determined by a configuration of lines. Although the proof given by De Bruijn and Erdős is combinatorial, De Bruijn and Erdős noted in their paper that the analogous (Euclidean) result is a consequence of the Sylvester–Gallai theorem, by an induction on the number of points.
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En (en), le théorème de De Bru ...... rence sur le nombre de points.
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In incidence geometry, the De ...... ction on the number of points.
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Теорема де Брёйна — Эрдёша — о ...... ресечений конфигурации прямых.
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author1-link
Nicolaas Govert de Bruijn
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author2-link
Paul Erdős
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first
Nicolaas Govert
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Paul
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Erdős
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de Bruijn
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comment
En (en), le théorème de De Bru ...... rence sur le nombre de points.
@fr
In incidence geometry, the De ...... ction on the number of points.
@en
Теорема де Брёйна — Эрдёша — о ...... ресечений конфигурации прямых.
@ru
label
De Bruijn–Erdős theorem (incidence geometry)
@en
Théorème de De Bruijn-Erdős (géométrie d'incidence)
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Теорема де Брёйна — Эрдёша
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