Mathematical Basics and 2D Euclidean Geometric Algebra
Published in Dietmar Hildenbrand, Introduction to Geometric Algebra Computing, 2020
Dietmar Hildenbrand
While the pairwise orthogonal and normalized basis vectors e1, e2,…, en are the basic algebraic elements of an n-dimensional vector algebra, they are only one part of the algebraic elements of an n-dimensional Geometric Algebra1. Blades are the basic algebraic elements of Geometric Algebra. An n-dimensional Geometric Algebra consists of blades with grades 0, 1, 2, …, n, where a scalar is a 0-blade (a blade of grade 0) and the 1-blades are the basis vectors e1, e2,…, en. The 2-blades2ei ∧ ej are blades spanned by two 1-blades, and so on. There exists only one element of the maximum grade n, I = e1 ∧ e2…∧en. It is therefore also called the pseudoscalar. A linear combination of k-blades is called a k-vector (or a vector, bivector, trivector….). A linear combination of blades with different grades is called a multivector. Multivectors are the general elements of a Geometric Algebra.