71 research outputs found
The right angle to look at orthogonal sets
If X and Y are orthogonal hyperdefinable sets such that X is simple, then any
group G interpretable in (X,Y) has a normal hyperdefinable X-internal subgroup
N such that G/N is Y-internal; N is unique up to commensurability. In order to
make sense of this statement, local simplicity theory for hyperdefinable sets
is developped. Moreover, a version of Schlichting's Theorem for hyperdefinable
families of commensurable subgroups is shown
SHELAH-STRONG TYPE AND ALGEBRAIC CLOSURE OVER A HYPERIMAGINARY (Model theoretic aspects of the notion of independence and dimension)
We characterize Shelah-strong type over a hyperimagianary with the algebraic closure of a hyperimaginary. Also, we present and take a careful look at an example that witnesses acl[eq](ℯ) is not interdefinable with acl(ℯ) where ℯ is a hyperimaginary
Binary simple homogeneous structures are supersimple with finite rank
Suppose that M is an infinite structure with finite relational vocabulary
such that every relation symbol has arity at most 2. If M is simple and
homogeneous then its complete theory is supersimple with finite SU-rank which
cannot exceed the number of complete 2-types over the empty set
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