In quantum mechanics, a spinor is a mathematical object that describes the intrinsic angular momentum, or "spin," of subatomic particles such as electrons. Spinors are elements of a complex number-based vector space that can be associated with Euclidean space or Minkowski space. They transform linearly under the action of the Lorentz group, which plays the role of rotations in Minkowski space. The space of spinors is formally defined as the fundamental representation of the Clifford algebra, and it may also be defined as a spin representation of the orthogonal Lie algebra. Dirac spinors are a specific type of spinor that describe all known fundamental particles that are fermions, with the possible exception of neutrinos. Spinors are important in quantum mechanics because they are used to describe the wave function of particles with half-integer spin.