English

Transcendental Groups

General Topology 2021-12-24 v1

Abstract

In this note we introduce the notion of a transcendental group, that is, a subgroup GG of the topological group C\mathbb{C} of all complex numbers such that every element of GG except 0 0 is a transcendental number. All such topological groups are separable metrizable zero-dimensional torsion-free abelian groups. Further, each transcendental group is homeomorphic to a subspace of N0\mathbb{N}^{\aleph_0}, where N\mathbb{N} denotes the discrete space of natural numbers. It is shown that (i) each countably infinite transcendental group is a member of one of three classes, where each class has c\mathfrak{c} (the cardinality of the continuum) members -- the first class consists of those isomorphic as a topological group to the discrete group \ZZ\ZZ of integers, the second class consists of those isomorphic as a topological group to \ZZ×\ZZ\ZZ\times \ZZ, and the third class consists of those homeomorphic to the topological space \QQ\QQ of all rational numbers; (ii) for each cardinal number \aleph with 0<\cc\aleph_0< \aleph\le \cc, there exist 22^\aleph transcendental groups of cardinality \aleph such that no two of the transcendental groups are isomorphic as topological groups or even homeomorphic; (iii) there exist c\mathfrak{c} countably infinite transcendental groups each of which is homeomorphic to \QQ\QQ and algebraically isomorphic to a vector space over the field \AAA\AAA of all algebraic numbers (and hence also over \QQ\QQ) of countably infinite dimension; (iv) \RR\RR has 2\cc2^\cc transcendental subgroups, each being a zero-dimensional metrizable torsion-free abelian group, such that no two of the transcendental groups are isomorphic as topological groups or even homeomorphic.

Keywords

Cite

@article{arxiv.2112.12450,
  title  = {Transcendental Groups},
  author = {Sidney A. Morris},
  journal= {arXiv preprint arXiv:2112.12450},
  year   = {2021}
}
R2 v1 2026-06-24T08:29:22.438Z