Elementary Properties of Cycle-free Partial Orders and their Automorphism Groups
نویسنده
چکیده
1. Abstract A classiication was given in 1, 12, 13] of all the countable k-CS-transitive cycle-free partial orders for k 3. Here the elementary theories of these structures and their automorphism groups are examined, and it is shown that in many cases we can distinguish the structures or their groups by means of their rst or second order properties. The small index property is established for weakly 2-transitive trees, and for several classes of cycle-free partial orders.
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ورودعنوان ژورنال:
- Order
دوره 18 شماره
صفحات -
تاریخ انتشار 2001