In: Vychisl. Sist. Vol. 119, pages 62-70. 1987. In Russian.
Abstract: An arbitrary digraph can be considered as an ordinary marked net of Petri. In the paper the algorithm for finding invariants in the nets of Petri is used in the search of simple contours in a digraph.
Keywords: contour (in a) >digraph; invariant (of a net); matrix algorithm.