Geometry

General position subsets ★★

Author(s): Gowers

Question   What is the least integer $ f(n) $ such that every set of at least $ f(n) $ points in the plane contains $ n $ collinear points or a subset of $ n $ points in general position (no three collinear)?

Keywords: general position subset, no-three-in-line problem

Posted by David Wood
updated March 24th, 2014
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Graph Theory » Coloring

Colouring $d$-degenerate graphs with large girth ★★

Author(s): Wood

Question   Does there exist a $ d $-degenerate graph with chromatic number $ d + 1 $ and girth $ g $, for all $ d \geq 2 $ and $ g \geq 3 $?

Keywords: degenerate; girth

Posted by David Wood
updated March 16th, 2014
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