Abstract
IfS is a strong Dubreil-Jacotin regular semigroup thenx∈S is said to beperfect ifx=x(ξ∶x)x where ζ is the bimaximum element ofS. It is shown that the setP(S) of perfect elements is an ideal ofS, and is also a strong Dubreil-Jacotin subsemigroup. It is then proved that every element ofS is perfect if and only ifS is naturally ordered. Finally, necessary and sufficient conditions forP(S) to be orthodox are determined.
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Communicated by R. McFadden
Support from the Junta Nacional de Investigação Científica e Tecnológica of Portugal is gratefully acknowledged.
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Blyth, T.S., Giraldes, E. Perfect elements in Dubreil-Jacotin regular semigroups. Semigroup Forum 45, 55–62 (1992). https://doi.org/10.1007/BF03025749
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DOI: https://doi.org/10.1007/BF03025749