The Living Thing / Notebooks :

Geometric algebra

as opposed to algebraic geometric.

Clifford algebras, generalised quaternions, the logarithm of a sphere, tensors, spinors, spinsters, tenors…

Alan Macdonald: Geometric Algebra:

Geometric algebra and its extension to geometric calculus unify, simplify, and generalize vast areas of mathematics that involve geometric ideas, including linear algebra, multivariable calculus, real analysis, complex analysis, and euclidean, noneuclidean, and projective geometry. They provide a unified mathematical language for physics (classical and quantum mechanics, electrodynamics, relativity), the geometrical aspects of computer science (e.g., graphics, robotics, computer vision), and engineering.
DoLa03
Doran, C., & Lasenby, A. N.(2003) Geometric algebra for physicists. . Cambridge ; New York: Cambridge University Press
LaLD00
Lasenby, J., Lasenby, A. N., & Doran, C. J. L.(2000) A unified mathematical language for physics and engineering in the 21st century. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 358(1765), 21–39. DOI.
Mcdo00
McDonald, A. (n.d.) A Survey of Geometric Algebra and Geometric Calculus.