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JSYML
2007
49views more  JSYML 2007»
13 years 4 months ago
On sets not belonging to algebras
Let A1, . . . , An, An+1 be a finite sequence of algebras of sets given on a set X, n k=1 Ak = P(X), with more than 4 3 n pairwise disjoint sets not
L. S. Grinblat
JSYML
2007
66views more  JSYML 2007»
13 years 4 months ago
Spectra of structures and relations
We consider embeddings of structures which preserve spectra: if g : M → S with S computable, then M should have the same Turing degree spectrum (as a structure) that g(M) has (a...
Valentina S. Harizanov, Russel G. Miller
JSYML
2007
68views more  JSYML 2007»
13 years 4 months ago
Reconstruction of homogeneous relational structures
Silvia Barbina, Dugald Macpherson
JSYML
2007
68views more  JSYML 2007»
13 years 4 months ago
Bounding nonsplitting enumeration degrees
We show that every nonzero Σ0 2 enumeration degree bounds a nonsplitting nonzero enumeration degree.
Thomas F. Kent, Andrea Sorbi
JSYML
2007
36views more  JSYML 2007»
13 years 4 months ago
Groups definable in ordered vector spaces over ordered division rings
Let M = M, +, <, 0, {λ}λ∈D be an ordered vector space over an ordered division ring D, and G = G, ⊕, eG an n-dimensional group definable in M. We show that if G is defin...
Pantelis E. Eleftheriou, Sergei Starchenko
JSYML
2007
85views more  JSYML 2007»
13 years 4 months ago
Lower bounds for modal logics
We give an exponential lower bound on number of proof-lines in the proof system K of modal logic, i.e., we give an example of K-tautologies 1, 2, . . . s.t. every K-proof of i must...
Pavel Hrubes
JSYML
2007
106views more  JSYML 2007»
13 years 4 months ago
Characterizing rosy theories
We examine several conditions, either the existence of a rank or a particular property of þ-forking that suggest the existence of a well-behaved independence relation, and determi...
Clifton Ealy, Alf Onshuus
JSYML
2007
58views more  JSYML 2007»
13 years 4 months ago
Bounding homogeneous models
A Turing degree d is homogeneous bounding if every complete decidable (CD) theory has a d-decidable homogeneous model A, i.e., the elementary diagram De (A) has degree d. It follo...
Barbara F. Csima, Valentina S. Harizanov, Denis R....