No CrossRef data available.
Published online by Cambridge University Press: 20 November 2018
By a PQ (product-quotients) algebra, we mean a non-empty set together with three single-valued and not necessarily associative operations ., / , \ that we shall treat as product, right quotient, and left quotient although we require no relation between them. The theory of binary systems provides the following examples:
A. is the set of all subsets of a groupoid G (which may be a semigroup) with the operations defined by: