Abstract
We obtain analogues, in the setting of semigroups with zero, of McAlister's covering theorem and the structure theorems of McAlister, O'Carroll, and Margolis and Pin. The covers come from a class C of semigroups defined by modifying one of the many characterisations of E-unitary inverse semigroups, namely, that an inverse semigroup is E-unitary if and only if it is an inverse image of an idempotent-pure homomorphism onto a group. The class C is properly contained in the class of all E*-unitary inverse semigroups introduced by Szendrei but properly contains the class of strongly categorical Ef-unitary semigroups recently considered by Comes and Howie.
Original language | English |
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Pages (from-to) | 15-30 |
Number of pages | 16 |
Journal | Journal of the australian mathematical society series a-Pure mathematics and statistics |
Volume | 67 |
Publication status | Published - Aug 1999 |
Keywords
- P-theorem
- E*-unitary
- cover
- SEMILATTICES