‎Let $G=(V‎, ‎E)$ be a simple graph‎. ‎A set $C$ of vertices of $G$ is an identifying code of $G$ if for every two vertices $x$ and $y$ the sets $N_{G}[x] \cap C$ and $N_{G}[y] \cap C$ are non-empty and different‎. ‎Given a graph $G,$ the smallest size of an identifying code of $G$ is called the identifying code number of $G$ and denoted by $\gamma^{ID}(G).$ In this paper‎, ‎we prove that the identifying code number of the subdivision of a graph $G$ of order $n$ is at most $n$‎. ‎Also‎, ‎we prove that the identifying code number of the subdivision of graphs $K_n$, $K_{r,s}$ and $C_P(s)$ are $n‎$,‎ ‎‎‎$‎‎r+s$ and $2s$, respectively‎. ‎Finally‎, ‎we conjecture that for every graph $G$ of order $n$ the identifying code number of the subdivision of $G$ is $n$‎.

‎Let $G=(V‎, ‎E)$ be a simple graph‎. ‎A set $C$ of vertices of $G$ is an identifying code of $G$ if for every two vertices $x$ and $y$ the sets $N_{G}[x] \cap C$ and $N_{G}[y] \cap C$ are non-empty and different‎. ‎Given a graph $G,$ the smallest size of an identifying code of $G$ is called the identifying code number of $G$ and denoted by $\gamma^{ID}(G).$ In this paper‎, ‎we prove that the identifying code number of the subdivision of a graph $G$ of order $n$ is at most $n$‎. ‎Also‎, ‎we prove that the identifying code number of the subdivision of graphs $K_n$, $K_{r,s}$ and $C_P(s)$ are $n‎$,‎ ‎‎‎$‎‎r+s$ and $2s$, respectively‎. ‎Finally‎, ‎we conjecture that for every graph $G$ of order $n$ the identifying code number of the subdivision of $G$ is $n$‎.

Let $G=(V, E)$ be a simple graph. A set $C$ of vertices $G$ is an identifying set of $G$ if for every two vertices $x$ and $y$ belong to $V$ the sets $N_{G}[x] \cap C$ and $N_{G}[y] \cap C$ are non-empty and different. Given a graph $G,$ the smallest size of an identifying set of $G$ is called the identifying code number of $G$ and is denoted by $\gamma^{ID}(G).$ Two vertices $x$ and $y$ are twins when $N_{G}[x]=N_{G}[y].$ Graphs with at least two twin vertices are not identifiable graphs. In this paper,  we present three bounds for identifying code number.

‎Consider a graph $G=(V(G),E(G))$‎, ‎where a perfect matching in $G$ is defined as a subset of independent edges with $\frac{|V(G)|}{2}$ elements‎. ‎A global forcing set is a subset $S$ of $E$ such that no two disjoint perfect matchings of $G$ coincide on it‎. ‎The minimum cardinality of global forcing sets of $G$ is called the global forcing number (GFN for short)‎. ‎This paper addresses the NP-hard problem of determining the global forcing number for perfect matchings‎. ‎The focus is on a Genetic Algorithm (GA) that utilizes binary encoding and standard genetic operators to solve this problem‎. ‎The proposed algorithm is implemented on some chemical graphs to illustrate the validity of the algorithm‎. ‎The solutions obtained by the GA are compared with the results from other methods that have been presented in the literature‎. ‎The presented algorithm can be applied to various bipartite graphs‎, ‎particularly hexagonal systems‎. ‎Additionally‎, ‎the results of the GA improve some results that‎ have already been presented for finding GFN‎.

A watching system in a graph G=(V, E) is a set W={w1, w2, …,wk}, where wi=(vi, Zi); viÎ V and Zi is a subset of closed neighborhood of vi such that the sets LW(v) ={wi: vÎZi} are non-empty and distinct, for any v ÎV. In this paper, we study the watching systems of line graph Kn which is called triangular graph and denoted by T (n). The minimum size of a watching system of G is denoted by w (G). We show that w (T(n))= [2n/3].