BCONTRACTIONS AND OTHER INNER PRODUCTS
This appendix collects some additional facts about contractions and inner products to give the correspondence with much other literature, as well as three long proofs for statements in Chapter 3.
B.1 OTHER INNER PRODUCTS
When you study the applied literature on geometric algebra, you will find an inner product used that is similar to the contraction, but not identical to it. It was originally introduced by Hestenes in , so we refer to it as the Hestenes inner product in this text. We define it here, and relate it to the contraction. It is most convenient to do so via an intermediate construction, the “dot product.” More detail about these issues may be found in , which defends the contraction in ...