On the number of finite algebraic structures

We prove that every clone of operations on a finite set $A$, if it contains a Malcev operation, is finitely related – i.e., identical with the clone of all operations respecting $R$ for some finitary relation $R$ over $A$. It follows that for a fixed finite set $A$, the set of all such Malcev clones...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Journal of the European Mathematical Society : JEMS 2014-01, Vol.16 (8), p.1673-1686
Hauptverfasser: Aichinger, Erhard, Mayr, Peter, McKenzie, Ralph
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:We prove that every clone of operations on a finite set $A$, if it contains a Malcev operation, is finitely related – i.e., identical with the clone of all operations respecting $R$ for some finitary relation $R$ over $A$. It follows that for a fixed finite set $A$, the set of all such Malcev clones is countable. This completes the solution of a problem that was first formulated in 1980, or earlier: how many Malcev clones can finite sets support? More generally, we prove that every finite algebra with few subpowers has a finitely related clone of term operations. Hence modulo term equivalence and a renaming of the elements, there are only countably many finite algebras with few subpowers, and thus only countably many finite algebras with a Malcev term.
ISSN:1435-9855
1435-9863
DOI:10.4171/JEMS/472