Completions for partially ordered semigroups |
| |
Authors: | M Erné J Z Reichman |
| |
Institution: | 1. Institut für Mathematik, Universit?t Hannover, 3000, Hannover 1, Federal Republic of Germany 2. Department of Mathematics, Hofstra University, Hempstead, N.Y., USA
|
| |
Abstract: | A standard completion γ assigns a closure system to each partially ordered set in such a way that the point closures are precisely
the (order-theoretical) principal ideals. If S is a partially ordered semigroup such that all left and all right translations
are γ-continuous (i.e., Y∈γS implies {x∈S:y·x∈Y}∈γS and {x∈S:x·y∈Y}∈γS for all y∈S), then S is called a γ-semigroup. If S
is a γ-semigroup, then the completion γS is a complete residuated semigroup, and the canonical principal ideal embedding of
S in γS is a semigroup homomorphism. We investigate the universal properties of γ-semigroup completions and find that under
rather weak conditions on γ, the category of complete residuated semigroups is a reflective subcategory of the category of
γ-semigroups. Our results apply, for example, to the Dedekind-MacNeille completion by cuts, but also to certain join-completions
associated with so-called “subset systems”. Related facts are derived for conditional completions.
A first draft of this paper by the second author, containing parts of Section 2, was received on August 9, 1985. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|