Multiplicative Distance-Location Number of Graphs

For a set \( S \) of vertices in a connected graph \( G \), the multiplicative distance of a vertex \( v \) with respect to \( S \) is defined by \(dS*(v) = ∏x ∈ S, x ≠ v d(v,x).\) If \( dS*(u) ≠ dS*(v) \) for each pair \( u,v \) of distinct vertices of \( G \), then \( S \) is called a multiplicative distance-locating set of \( G \). The minimum cardinality of a multiplicative distance-locating set of \( G \) is called its multiplicative distance-location number \( locd*(G) \). If \( dS*(u) ≠ dS*(v) \) for each pair \( u,v \) of distinct vertices of \( G-S \), then \( S \) is called an external multiplicative distance-locating set of \( G \). The minimum cardinality of an external multiplicative distance-locating set of \( G \) is called its external multiplicative location number \( locₑ*(G) \). We prove the existence or non-existence of multiplicative distance-locating sets in some well-known classes of connected graphs. Also, we introduce a family of connected graphs such that \( locd*(G) \) exists. Moreover, there are infinite classes of connected graphs \( G \) for which \( locd*(G) \) exists as well as infinite classes of connected graphs \( G \) for which \( locd*(G) \) does not exist. A lower bound for the multiplicative distance-location number of a connected graph is established in terms of its order and diameter.