Schreier extensions of semigroups
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Nguyen Huu Khang
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Article
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1983
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John Wiley and Sons
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English
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Let G, H be groups. G is called an extension of H if there is an epimorphism u: G + H . The congruence Ker u is uniquely determined by the normal subgroups N = o-l( la). Thus we may say that G is an extension of H by N . Analogously a monoid S is called an extension of a monoid C if there is an epi