Syntactic and Rees indices of subsemigroups

Nikola Ruskuc, RM Thomas

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


We define two different notions of index for subsemigroups of semigroups: the (right) syntactic index and the Rees index We investigate the relationships between them and with the group index. In particular, we show that the syntactic index is a generalisation of both the group index and the Rees index. Fire use this fact to prove further similarities between the group index and the Rees index. It turns out, however, that very few of the nice properties of the group index are inherited by the syntactic index. (C) 1998 Academic Press.

Original languageEnglish
Pages (from-to)435-450
Number of pages16
JournalJournal of Algebra
Publication statusPublished - 15 Jul 1998


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