IMO Shortlist 1977 problem 14
Kvaliteta:
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Avg: 0,0 Let be a finite set of points such that is not contained in a plane and no three points of are collinear. Show that at least one of the following alternatives holds:
(i) contains five points that are vertices of a convex pyramid having no other points in common with
(ii) some plane contains exactly three points from
(i) contains five points that are vertices of a convex pyramid having no other points in common with
(ii) some plane contains exactly three points from
Izvor: Međunarodna matematička olimpijada, shortlist 1977