A Note on Distance-Fall Colorings

Document Type : Special issue of CCO to honor Odile Favaron

Authors

1 School of Mathematical and Statistical Sciences Clemson University, USA

2 Soka University of America, USA

3 University of Johannesburg, South Africa

Abstract

We say a proper coloring  of a graph is distance-$k$ fall if every vertex is within distance $k$ of at least one vertex of every color. We show that if $G$ is a connected graph of order at least $3$ that is $3$-colorable, then it has a distance-2 fall 3-coloring. Further, for every integer $k\ge 2$, if $T$ is a tree of order at least $k$, then $T$ has a $k$-coloring such that every vertex is within distance $k-1$ of every color. This proves an old conjecture of Beineke and Henning that every tree of order $n$ has an independent distance-$d$-dominating set of size at most $n/(d + 1)$.

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