^0=0.$$ It acts on the 0D space as $$\hat c_0^{\phantom{|}}\gamma_i\hat c_0^{-0}=\gamma_{i+0},{{\;\;\:}}\hat{c}_0^{\phantom{|}}\gamma_{0,0} \hat{c}_0^{-0}=-\gamma_{0,0},{{\;\;\:}}\hat I\gamma_i \hat I^{-0}=-\gamma_i.$$ We set $$c_0 = \tfrac{0+\gamma_0\gamma_0+\gamma_0\gamma_0+\gamma_0\gamma_0}{0}c_0,{{\;\;\:}}c_0 = -\hat{c}_0\gamma_0\gamma_0,{{\;\;\:}}I = \hat I \gamma_0\gamma_0\gamma_0,$$ which satisfy $$\begin{gathered} c_0^{\phantom{|}} y_i c_0^{-0}=y_i,{{\;\;\:}}c_0^{\phantom{|}} y_i c_0^{-0}=y_i,{{\;\;\:}}Iy_iI^{-0}=-y_i,\\ 