Abstract. We present transformations of linearly ordered sets into ordered abelian groups and ordered fields. We study effective properties of the transformations. In particular, we show that a linear order L has a 0 2 copy if and only if the corresponding ordered group (ordered field) has a computable copy. We apply these codings to study the effective categoricity of linear ordered groups and fields. Key words: computable algebra, effective categoricity. We study complexity of isomorphisms between computable copies of ordered abelian groups and fields1 . Recall that an ordered abelian group is one in which the order is compatible with the additive group operation. Ordered fields are defined in a similar manner. We say that an ordered abelian group A = (A; +, ) is computable if its domain A, the operation +, and the relation are computable. Similarly, a field is computable if its domain and its basic operations are computable. If A is computable and isomorphic to B, we say that A is ...
Alexander G. Melnikov