INFINITE COMBINATORICS PLAIN AND SIMPLE

Autor: Dániel T. Soukup, Lajos Soukup
Rok vydání: 2018
Předmět:
Zdroj: The Journal of Symbolic Logic. 83:1247-1281
ISSN: 1943-5886
0022-4812
Popis: We explore a general method based on trees of elementary submodels in order to present highly simplified proofs to numerous results in infinite combinatorics. While countable elementary submodels have been employed in such settings already, we significantly broaden this framework by developing the corresponding technique for countably closed models of size continuum. The applications range from various theorems on paradoxical decompositions of the plane, to coloring sparse set systems, results on graph chromatic number and constructions from point-set topology. Our main purpose is to demonstrate the ease and wide applicability of this method in a form accessible to anyone with a basic background in set theory and logic.
Comment: 29 pages, small revisions, to appear in JSL
Databáze: OpenAIRE