Spinor dimension in arbitrary spacetime dimension (${\dim }_{\mathbb{C}}{S}_D=2^{\lfloor D/2\rfloor }$)

An irreducible complex Clifford algebra module in even spacetime dimension $2k$ has dimension $2^k$ and splits under the connected Spin group into two Weyl spinor modules of dimension $2^{k-1}$. In odd dimension $2k+1$, an irreducible spinor still has dimension $2^k$ but has no Weyl splitting. Reality conditions depend on signature and are additional to these complex counts.