Let 

 be a simple graph with vertex set 

 and edges set 

. A set 

 is a dominating
set if every vertex in 

 is adjacent to at least one vertex  in 

. An eternal 1-secure set of a graph G is defined as a dominating set 

 such that for any positive integer k and any sequence 

 of vertices, there exists a sequence of guards  

 with 

 and either 

 or 

 and 

 is a dominating set. If we take a guard on every vertex in an eternal 1-secure set, then for any sequence of attacks to vertices of the graph only by moving one guard during one of the edges adjacent with the vertex, the result set still remains secure. Now let for every sequence of attacks to vertices, all guards could move during one of the edges adjacent with the vertex and the result set still remains secure. This set is called eternal 

-  secure set. The eternal 

-  security number 

 is defined as the minimum number of an eternal 

- 

secure set. secure set in G. An edge 

 is subdivided if the edge 

 is deleted and a new vertex 

 is added, along with two new edges

 and 

. The eternal 

- security subdivision number 

 of a graph 

 is the minimum cardinality of a set of edges that must be subdivided (where each edge in 

 can be subdivided at most once) in order to increase the eternal 

- 

security number of 

 to increase the eternal m- security number of G. In this paper, we show that the eternal 

- security subdivision number is at most 3 for any nontrivial graph .
 
                    
 
                    
                    
                    Type of Study:  
S |
                    Subject: 
                    
Algebraic Graph Theory  Received: 2019/11/12 | Revised: 2022/11/15 | Accepted: 2020/08/5 | Published: 2022/05/14 | ePublished: 2022/05/14