Draw a planar finite non-empty set $S$ satisfying the following two conditions:
(a) every line meets $S$ in at most four points;
(b) every colouring of the elements of $S$ in one of two colours yields (at least) three monochromatic collinear points.
Fourth Problem, IMAR Competition 2012
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Laurențiu Ploscaru
- Mesaje: 1237
- Membru din: Mie Mai 04, 2011 5:42 pm
- Localitate: Călimănești
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Fourth Problem, IMAR Competition 2012
People are strange when you're a stranger,
Faces look ugly when you're alone.
Women seem wicked when you're unwanted,
Streets are uneven when you're down.
Faces look ugly when you're alone.
Women seem wicked when you're unwanted,
Streets are uneven when you're down.