Parcijalna uredjenja izomorfnih podstruktura relacijskih stuktura
Partial orders of isomorphic substructures of relational structures
Author
Kuzeljević, BorišaMentor
Kurilić, MilošCommittee members
Pilipović, StevanKurilić, Miloš
Grulović, Milan
Mijajlović, Žarko
Šobot, Boris
Metadata
Show full item recordAbstract
Cilj ove teze je da se ispitaju lanci u parcijalnim uredjenjima (P(X), ⊂), pri čemu je P(X) skup domena izomorfnih podstruktura relacijske strukture X. Pošto se svaki lanac u parcijalnom uredjenju može produžiti do maksimalnog lanca, dovoljno je ispitati maksimalne lance u P(X). Dokazano je da, ako je X ultrahomogena relacijska struktura koja ima netrivijalne izomorfne podstrukture, onda je svaki maksimalan lanac u (P(X) ∪ {∅} , ⊂) kompletno linearno uredjenje koje se utapa u R i ima neizolovan minimum. Ako je X relacijska struktura, dat je dovoljan uslov da za svako kompletno linearno uredjenje L koje se utapa u R i ima neizolovan minimum, postoji maksimalan lanac u (P(X) ∪ {∅} , ⊂) izomorfan L. Dokazano je i da ako je X neka od sledećih relacijskih struktura: Rado graf, Hensonov graf, random poset, ultrahomogeni poset Bn ili ultrahomogeni poset Cn; onda je L izomorfno maksimalnom lancu u (P(X) ∪ {∅} , ⊂) ako i samo ako je L kompletno, utapa se u R i ima neizolovan minimu...m. Ako je X prebrojiv antilanac ili disjunktna unija µ kompletnih grafova sa ν tačaka za µν = ω, onda je L izomorfno maksimalnom lancu u (P(X) ∪ {∅} , ⊂) ako i samo ako je bulovsko, utapa se u R i ima neizolovan minimum.
The purpose of this thesis is to investigate chains in partial orders (P(X), ⊂), where P(X) is the set of domains of isomorphic substructures of a relational structure X. Since each chain in a partial order can be extended to a maximal one, it is enough to describe maximal chains in P(X). It is proved that, if X is an ultrahomogeneous relational structure with non-trivial isomorphic substructures, then each maximal chain in (P(X)∪ {∅} , ⊂) is a complete, R-embeddable linear order with minimum non-isolated. If X is a relational structure, a condition is given for X, which is sufficient for (P(X) ∪ {∅} , ⊂) to embed each complete, R-embeddable linear order with minimum non-isolated as a maximal chain. It is also proved that if X is one of the follow- ing relational structures: Rado graph, Henson graph, random poset, ultrahomogeneous poset Bn or ultrahomogeneous poset Cn; then L is isomorphic to a maximal chain in (P(X) ∪ {∅} , ⊂) if and only if L is complete, R-embeddable wit...h minimum non-isolated. If X is a countable antichain or disjoint union of µ complete graphs with ν points where µν = ω, then L is isomorphic to a maximal chain in (P(X) ∪ {∅} , ⊂) if and only if L is Boolean, R-embeddable with minimum non-isolated.
Faculty:
Универзитет у Новом Саду, Природно-математички факултетDate:
02-06-2014Projects:
- Set Theory, Model Theory and Set-Theoretic Topology (RS-MESTD-Basic Research (BR or ON)-174006)