In Eq. (26.7), invert (A^{mu}(x)=A_{i}^{mu}(x) tau^{i}) to obtain (A_{i}^{mu}(x) equiv 2 operatorname{Tr}left(tau_{i} A^{mu} ight)).

In Eq. (26.7), invert \(A^{\mu}(x)=A_{i}^{\mu}(x) \tau^{i}\) to obtain \(A_{i}^{\mu}(x) \equiv 2 \operatorname{Tr}\left(\tau_{i} A^{\mu}\right)\).