Disproof of two conjectures on proper 2-dominating sets in graphs

Document Type : Short notes

Authors

1 LAMDA-RO Laboratory, Department of Mathematics, University of Blida, Blida, Algeria

2 Lehrstuhl II für Mathematik, RWTH Aachen, 52056 Aachen, Germany

Abstract

In this note, we disprove two conjectures recently stated on proper $2$-dominating sets in graphs. We recall that a proper $2$-dominating set of a graph $G=(V,E)$ is a subset $D$ of $V$ such that every vertex in $V-D$ has at least two neighbors in $D$ except for at least one vertex which must have exactly two neighbors in $D$.

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https://doi.org/10.3390/sym16030296
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