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Czech-Polish-Slovak Match
2019 Czech-Austrian-Polish-Slovak Match
3
3
Part of
2019 Czech-Austrian-Polish-Slovak Match
Problems
(1)
Placing arrows to form cycles
Source: Czech-Polish-Slovak Match 2019 P3
7/15/2019
A dissection of a convex polygon into finitely many triangles by segments is called a trilateration if no three vertices of the created triangles lie on a single line (vertices of some triangles might lie inside the polygon). We say that a trilateration is good if its segments can be replaced with one-way arrows in such a way that the arrows along every triangle of the trilateration form a cycle and the arrows along the whole convex polygon also form a cycle. Find all
n
≥
3
n\ge 3
n
≥
3
such that the regular
n
n
n
-gon has a good trilateration.
combinatorics