In differential geometry, given a spin structure on an n {\displaystyle n} -dimensional orientable Riemannian manifold ( M , g ) , {\displaystyle (M,g),\,} one defines the spinor bundle to be the complex vector bundle π S : S → M {\displaystyle \pi _{\mathbf {S} }\colon {\mathbf {S} }\to M\,} associated to the corresponding principal bundle π P : P → M {\displaystyle \pi _{\mathbf {P} }\colon {\mathbf {P} }\to M\,} of spin frames over M {\displaystyle M} and the spin representation of its structure group S p i n ( n ) {\displaystyle {\mathrm {Spin} }(n)\,} on the space of spinors Δ n {\displaystyle \Delta _{n}} .