MathJAX

When \(a \ne 0\), there are two solutions to \(ax^2 + bx + c = 0\) and they are
\[x = {-b \pm \sqrt{b^2-4ac} \over 2a}.\]

$$W_G^{mn}=max\{0,W_G.\xi_G(f_G^m,f_G^n)\}$$