Aiki (martial arts principle) and its practice is often kept within a particular individual or two from a family/school lineage. Culturally, and due to certain necessities of the time period, the aiki knowledge was usually a very well guarded secret and rarely disclosed. The oldest book to have historically discuss aiki was the 1899 Budo Hiketsu-Aiki no Jutsu. On the subject of aiki it was written: The Textbook of Jujutsu (Jujutsu Kyoju-sho Ryu no Maki) from 1913 wrote: Aiki (martial arts principle) Aiki from a Japanese budo term, at its most basic is a principle that allows a conditioned practitioner to negate or redirect
Orthogonality (term rewriting) Orthogonality (term rewriting) Orthogonality as a property of term rewriting systems describes where the reduction rules of the system are all left-linear, that is each variable occurs only once on the left hand side of each reduction rule, and there is no overlap between them. Orthogonal term rewriting systems have the consequent property that all reducible expressions (redexes) within a term are completely disjoint -- that is, the redexes share no common function symbol. For example, the term rewriting system with reduction rules is orthogonal -- it is easy to observe that each reduction rule is left-linear, and the left