A counterexample to the reconstruction of ω-categorical structures from their endomorphism monoid
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Contributors
Abstract
We present an example of two countable ω-categorical structures, one of which has a finite relational language, whose endomorphism monoids are isomorphic as abstract monoids, but not as topological monoids—in other words, no isomorphism between these monoids is a homeomorphism. For the same two structures, the automorphism groups and polymorphism clones are isomorphic, but not topologically isomorphic. In particular, there exists a countable ω-categorical structure in a finite relational language which can neither be reconstructed up to first-order biinterpretations from its automorphism group, nor up to existential positive bi-interpretations from its endomorphism monoid, nor up to primitive positive bi-interpretations from its polymorphism clone.
Details
Original language | English |
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Pages (from-to) | 57-82 |
Number of pages | 26 |
Journal | Israel journal of mathematics |
Volume | 224 |
Issue number | 1 |
Publication status | Published - 1 Apr 2018 |
Peer-reviewed | Yes |
External IDs
ORCID | /0000-0001-8228-3611/work/142241084 |
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