Digraphs in which ordered pairs of out- and in-degrees of vertices are mutually distinct are called irregular, see Gargano et al. [3]. Our investigations focus on the problem: what are possible sizes of irregular digraphs (oriented graphs) for a given order n? We show that those sizes in both cases make up integer intervals. The extremal sizes (the endpoints of these intervals) are found in [1,5]. In this paper we construct, with help of Sokoban-type game, n-vertex irregular oriented graphs (irregular digraphs) of all intermediate sizes.
@article{bwmeta1.element.bwnjournal-article-doi-10_7151_dmgt_1387, author = {Zyta Dziechci\'nska-Halamoda and Zofia Majcher and Jerzy Michael and Zdzis\l aw Skupie\'n}, title = {A Sokoban-type game and arc deletion within irregular digraphs of all sizes}, journal = {Discussiones Mathematicae Graph Theory}, volume = {27}, year = {2007}, pages = {611-622}, zbl = {1142.05036}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_7151_dmgt_1387} }
Zyta Dziechcińska-Halamoda; Zofia Majcher; Jerzy Michael; Zdzisław Skupień. A Sokoban-type game and arc deletion within irregular digraphs of all sizes. Discussiones Mathematicae Graph Theory, Tome 27 (2007) pp. 611-622. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_7151_dmgt_1387/
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