On the distance spectrum and distance energy of complement of subgroup graphs of dihedral group

Let G is a connected simple graph and V(G) = {v1, v2, ..., vp} is vertex set of G. The distance matrix of G is a matrix D(G) = [d ij ] of order p where [d ij ] = d(v i , v j ) is distance between v i and v j in G. The set of all eigenvalues of matrix D(G) together with their corresponding multiplicities is named the distance spectrum of G and denoted by spec D (G). The distance energy of G is ${E}_{D}(G)={\sum }_{i=1}^{p}|{\lambda }_{i}|$, where λi are eigenvalues of D(G). In the recent paper, the distance spectrum and distance energy of complement of subgroup graphs of dihedral group are determined