- Research Article
16
- 10.1007/s00493-003-0035-y
On a Generalization of R�dei?s Theorem
- Dec 01, 2003
- Combinatorica
- Andr�S G�Cs
In 1970 Redei and Megyesi proved that a set of p points in AG(2,p), p prime, is a line, or it determines at least $$\frac{{p + 3}} {2}$$ directions. In ’81 Lovasz and Schrijver characterized the case of equality. Here we prove that the number of determined directions cannot be between $$\frac{{p + 5}} {2}$$ and $$2\frac{{p - 1}} {3}$$. The upper bound obtained is one less than the smallest known example.
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