On Superstable Groups
نویسنده
چکیده
S. Shelah [20] has given a description of all countable complete theories T that permit a classification of their models. A necessary condition for T is superstability. A stable (superstable) group is a group interpreted in some stable (superstable) structure. It is equivalent to say that the groups investigated have additional relations and functions such that the whole structure is stable (superstable). We use Ho G to denote that H is a normal subgroup of G. For our purpose it is necessary to consider definable and A-definable subgroups in some stable (superstable) group G and also in definable quotients H/N in G, where H and N are definable subgroups in G and N<i H. We show the following.
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