Topological groups from matrices of sets

Abstract

We give a general construction of topological groups from combinatorial structures such as trees, towers, gaps, and subadditive functions. We connect topological properties of corresponding groups with combinatorial properties of these objects. For example, the group built from an ω1-tree is Fréchet if and only if the tree is Aronszajn. We also determine cofinal types of some of these groups under certain set theoretic assumptions.