Seidel spectrum

Seidel spectrum --- cпектр Зейделя.

The Seidel spectrum consists of the eigenvalues

[math]\displaystyle{ \lambda_{1}^{*} \geq \lambda_{2}^{*} \geq \cdots \lambda_{n}^{*} }[/math]

of its [math]\displaystyle{ (0,-1,1) }[/math] adjacency matrix [math]\displaystyle{ A^{*} = A^{*}(G) }[/math].

[math]\displaystyle{ P_{G}^{*}(\lambda) = |\lambda I - A^{*}| }[/math] denotes the Seidel characteristic polynomial.