On the Natural Order Relation in Peano Algebras with Finitary or Infinitary Operations
نویسنده
چکیده
Most work on infinitary algebras in the literature makes ample use of the axiom of choice AC (see, e.g., [10],[12],[14]). While the theory of arbitrary infinitary algebras can hardly be developed in a satisfactory manner without AC, in the case of Peano algebras (= word algebras, absolutely free algebras) many or even most of the basic results can be proved in Zermelo-Fraenkel set theory ZF without the axiom of choice, sometimes, however, only with considerable effort.
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