Clifford’s ‘geometric algebra‘ is presented as the natural language for expressing geometrical ideas in mathematical physics. Its spacetime version ‘spacetime algebra‘ is introduced and is shown to provide a powerful, invariant description of relativistic physics. Applications to electromagnetism and gravitation are discussed.
S. F. Gull, A. N. Lasenby and C. J. L. Doran, Geometric algebra, spacetime physics and gravitation, In O. Lahav, E. Terlevich and R. J. Terlevich, editors, Gravitational Dynamics, (Cambridge University Press, 1996), pp. 171-180.