Monochromatic configurations on a circle

Gábor Damásdi, Nóra Frankl, János Pach +1

If we two-colour a circle, we can always find an inscribed triangle with angles $(\frac{\ddot{I}}{€}7,\frac{2\ddot{I}€}{7},\frac{4\ddot{I}€}{7})$ whose three vertices have the same colour. In fact, Bialo…