According to an old theorem of Yeager (Trans Am Math Soc 215:253–267, 1976), a homomorphism h:X→Y\documentclass[12pt]{minimal}
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\begin{document}$$h:X\rightarrow Y$$\end{document} between compact Hausdorff topological Clifford semigroups is continuous if and only if for every subgroup H⊂X\documentclass[12pt]{minimal}
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\begin{document}$$H\subset X$$\end{document} and every subsemilattice E⊂X\documentclass[12pt]{minimal}
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\begin{document}$$E\subset X$$\end{document} the restrictions h|H\documentclass[12pt]{minimal}
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\begin{document}$$h|H$$\end{document} and h|E\documentclass[12pt]{minimal}
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\begin{document}$$h|E$$\end{document} are continuous. In this paper we extend this Yeager result beyond the class of compact topological Clifford semigroups.
机构:
Univ Ljubljana, Fac Math & Phys, Ljubljana 1001, Slovenia
Univ Ljubljana, Fac Educ, Ljubljana 1001, SloveniaIvan Franko Lviv Natl Univ, Dept Mech & Math, UA-79000 Lvov, Ukraine