If \(T^{i_1\dots i_r}\) are the components of a \((r,0)\) tensor, \(T\), with respect to some basis then the symmetrization of \(T\), \(S(T)\), has components which are conventionally denoted, \(T^{(i_1\dots i_r)}\). That is, by definition,
\begin{equation}
T^{(i_1\dots i_r)}=\frac{1}{r!}\sum_{\sigma\in S_r}T^{i_{\sigma(1)}\dots i_{\sigma(r)}}.
\end{equation}
Similarly, the antisymmetrization of \(T\), \(A(T)\), has components which are conventionally deonted, \(T^{[i_1\dots i_r]}\). That is, by definition,
\begin{equation}
T^{[i_1\dots i_r]}=\frac{1}{r!}\sum_{\sigma\in S_r}\sgn(\sigma)T^{i_{\sigma(1)}\dots i_{\sigma(r)}}.
\end{equation}