DMGT

Discussiones Mathematicae Graph Theory 21(1) (2001) 207-221
DOI: https://doi.org/10.7151/dmgt.1144

ON VARIETIES OF ORGRAPHS

Alfonz Haviar and Gabriela Monoszová

Department of Mathematics, Faculty of Natural Sciences
Matej Bel University, Tajovského 40, 974 01
Banská Bystrica, Slovakia
e-mail: haviar.umb.sk
e-mail: monosz.umb.sk

Abstract

In this paper we investigate varieties of orgraphs (that is, oriented graphs) as classes of orgraphs closed under isomorphic images, suborgraph identifications and induced suborgraphs, and we study the lattice of varieties of tournament-free orgraphs.

Keywords: orgraph, variety, lattice.

2000 Mathematics Subject Classification: 05C20.

References

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Received 13 November 2000
Revised 16 May 2001