Authors: L. Shahbaz
Abstract
In this paper, after recalling the category {\bf PosAct}-$S$ of all poset acts over a pomonoid $S$;
an $S$-act in the category {\bf Pos} of all posets, with action
preserving monotone maps between them, some categorical properties of
the category {\bf PosAct}-$S$ are considered. In particular,
we describe limits and colimits such as products, coproducts, equalizers, coequalizers and etc. in this category.
Also, several kinds of epimorphisms and monomorphisms are characterized in {\bf PosAct}-$S$.
Finally, we study injectivity and projectivity in {\bf PosAct}-$S$ with respect to (regular) monomorphisms and (regular) epimorphisms,
respectively, and see that although there is no non-trivial injective poset act with respect to monomorphisms, {\bf PosAct}-$S$
has enough regular injectives with respect to regular monomorphisms. Also, it is proved that regular injective poset acts are exactly retracts of cofree poset acts over
complete posets.
Department of Mathematics, University of Maragheh, Maragheh, 55181-83111 Iran
E-mail: ,
DOI
https://doi.org/10.56415/qrs.v31.11
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