The $k$-metric dimension of the lexicographic product of graphs
  Given a simple and connected graph $G=(V,E)$, and a positive integer $k$, a set $S\subseteq V$ is said to be a $k$-metric generator for $G$, if for any pair of different vertices $u,v\in V$, there exist at least $k$ vertices $w_1,w_2,\ldots,w_k\in S$ such that $d_G(u,w_i)\ne d_G(v,w_i)$, for every $i\in \{1,\ldots,k\}$, where $d_G(x,y)$ denotes the distance between $x$ and $y$. The minimum cardinality of a $k$-metric generator is the $k$-metric dimension of $G$. A set $S\subseteq V$ is a $k$-adjacency generator for $G$ if any two different vertices $x,y\in V(G)$ satisfy $|((N_G(x)\triangledown N_G(y))\cup\{x,y\})\cap S|\ge k$, where $N_G(x)\triangledown N_G(y)$ is the symmetric difference of the neighborhoods of $x$ and $y$. The minimum cardinality of any $k$-adjacency generator is the $k$-adjacency dimension of $G$. In this article we obtain tight bounds and closed formulae for the $k$-metric dimension of the lexicographic product of graphs in terms of the $k$-adjacency dimension of the factor graphs. 
A. Estrada-Moreno, I. G. Yero, J. A. Rodr\'iguez-Vel\'azquez
math.CO