Discussiones
Mathematicae General Algebra and Applications 21(2) (2001)201-205
DOI: https://doi.org/10.7151/dmgaa.1037
MINIMAL FORMATIONS OF UNIVERSAL ALGEBRAS
Wenbin Guo Department of Mathematics, |
K.P. Shum Department of Mathematics, |
Abstract
A class F of universal algebras is called a formation if the following conditions are satisfied: 1) Any homomorphic image of A Î F is in F; 2) If a1, a2 are congruences on A and A/ai Î F, i = 1,2, then A/(a1Ça2) Î F. We prove that any formation generated by a simple algebra with permutable congruences is minimal, and hence any formation containing a simple algebra, with permutable congruences, contains a minimum subformation. This result gives a partial answer to an open problem of Shemetkov and Skiba on formations of finite universal algebras proposed in 1989.Keywords: universal algebra; congruence; formation; minimal subformation.
2000 AMS Mathematics Subject Classifications: 03C05, 08B05, 08B10.
References
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Received 29 March 2001
Revised 25 September 2001