What is a Graph? · Graphs

Lesson 6

Nikolai Chukhin · Alexander S. Kulikov

In terms of our graph, the problem is stated as follows.

It is not difficult to see that this exchange is impossible: since two knights are not allowed to occupy the same cell, no matter how they move, the color of the knights will always alternate along the circle.

Curiously, besides the board graph considered above, there is another graph connected to Guarini's puzzle, a configuration graph. We will soon discover it.