maximizing distances of regular polygons on a circle; transport problems; $M$-system; $M$-graph; determination of optimal solution; bus line scheduling
This paper presents the solution of a basic problem defined by J. Černý which solves a concrete everyday problem in railway and road transport (the problem of optimization of time-tables by some criteria).
 J. Černý: Problems for systems of regular polygons on a circumference and their application in transport. (Czech). Matematické obzory (1972), 51 - 59.
 J. Černý: Applied mathematics and transport
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 F. Harrary: Graph Theory
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