TY - JOUR
T1 - Many symmetrically indivisible structures
AU - Meir, Nadav
N1 - Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - A structure M in a first-order language L is indivisible if for every colouring of its universe M in two colours, there is a monochromatic M′⊆M such that M′≅M. Additionally, we say that M is symmetrically indivisible if M′ can be chosen to be symmetrically embedded in M (that is, every automorphism of M′ can be extended to an automorphism of M). In the following paper we give a general method for constructing new symmetrically indivisible structures out of existing ones. Using this method, we construct 2ℵ0 many non-isomorphic symmetrically indivisible countable structures in given (elementary) classes and answer negatively the following question from : Let M be a symmetrically indivisible structure in a language L. Let L0⊆L. Is M{up harpoon right}L0 symmetrically indivisible?.
AB - A structure M in a first-order language L is indivisible if for every colouring of its universe M in two colours, there is a monochromatic M′⊆M such that M′≅M. Additionally, we say that M is symmetrically indivisible if M′ can be chosen to be symmetrically embedded in M (that is, every automorphism of M′ can be extended to an automorphism of M). In the following paper we give a general method for constructing new symmetrically indivisible structures out of existing ones. Using this method, we construct 2ℵ0 many non-isomorphic symmetrically indivisible countable structures in given (elementary) classes and answer negatively the following question from : Let M be a symmetrically indivisible structure in a language L. Let L0⊆L. Is M{up harpoon right}L0 symmetrically indivisible?.
UR - http://www.scopus.com/inward/record.url?scp=84939424211&partnerID=8YFLogxK
U2 - 10.1002/malq.201400091
DO - 10.1002/malq.201400091
M3 - Article
AN - SCOPUS:84939424211
SN - 0942-5616
VL - 61
SP - 341
EP - 346
JO - Mathematical Logic Quarterly
JF - Mathematical Logic Quarterly
IS - 4-5
ER -