Triangles in arrangements of lines
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G.B. Purdy
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Article
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1979
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Elsevier Science
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English
โ 486 KB
A set of n nonconcurrent lines in the projective plane (called an arrangement) divides the plane into polygonal cells. It has long been a problem to find a nontrivial upper bound on the number of triangular regions. We show that &n(n -1) is such a bound. We also show that if no three lines are concu