Optimum skew energy of a tournament

Let G be a simple undirected graph and G^σ the corresponding oriented graph of G with the orientation σ. The skew energy of G^σ, denoted by ε(G^σ), is defined as the sum of the singular values of its skew adjacency matrix S(G^σ). In 2010, Adiga et al. proved ε(G^σ)≤nΔ, where Δ is the maximum degree of G of order n. In this paper, we characterize the skew energy of a tournament and present some properties about an optimum skew energy tournament.