2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/153362A new notion of an optimal algebra for a first order coordinate differential was introduced in \cite{BKO}. Some relevant examples are indicated. Quadratic identities in the optimal algebras and calculi on quadratic algebras are studied. Canonical construction of a quantum de Rham complex for the coordinate differential is proposed. The relations between calculi and various generalizations of the Yang--Baxter equation are established.contribution to the Proc. XXX Winter School of Theoretical Physics in Karpacz 1994, 11 pages, LaTeXQuantum Algebratext