Grassmann-valued SU(2) adjoint bracket (source code)

= Grassmann-valued SU(2) adjoint bracket
{c}
{title2=$(X\times Y)_a=\varepsilon_{abc}X_bY_c$}

For adjoint fields whose coefficients have <Grassmann parity>, $X\times Y=-(-1)^{|X||Y|}Y\times X$. Thus two odd ghost fields have a symmetric adjoint bracket, and $c\times c$ need not vanish. The <graded Jacobi identity> and this symmetry are the algebraic mechanisms behind <BRST nilpotence>.