J Austral Math Soc Ser A 56 pp212--231, 1994.
(Received 26 July 1991)
The free product *CRSi of an arbitrary family of disjoint simple semigroups {Si}i Î I, within the variety CR of completely regular semigroups, is described by means of a theorem generalizing that of Kadourek and Polak for free completely regular semigroups. A notable consequence of the description is that all maximal subgroups of *CRSi are free, except for those in the factors Si themselves. The general theorem simplifies in the case of free CR-products of groups and, in particular, free idempotent-generated completely regular semigroups.
1991 AMS Subject Classification: primary 20M05; secondary 08A50
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