Axiomatisability of free, projective and flat S-acts
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چکیده
We survey the known results characterising those monoids S such that the classes of free, projective or (weakly, strongly) flat S-acts are first order axiomatisable. The conditions on the monoid S that arise are finitary, and intricately related. We examine their inter-connections and illustrate the independence of certain pairs.
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تاریخ انتشار 2007