# Metric Spaces in Synthetic Topology

- 06 January 2010
- Constructive math, Publications

With Davorin Lešnik.

**Abstract:** We investigate the relationship between the synthetic approach to topology, in which every set is equipped with an intrinsic topology, and constructive theory of metric spaces. We relate the synthetic notion of compactness of Cantor space to Brouwer’s Fan Principle. We show that the intrinsic and metric topologies of complete separable metric spaces coincide if they do so for Baire space. In Russian Constructivism the match between synthetic and metric topology breaks down, as even a very simple complete totally bounded space fails to be compact, and its topology is strictly finer than the metric topology. In contrast, in Brouwer’s intuitionism synthetic and metric notions of topology and compactness agree.

**Download paper:** csms_in_synthtop.pdf

##### Post a comment:

`$⋯$`

for inline and `$$⋯$$`

for display LaTeX formulas,
and `<pre>⋯</pre>`

for display code. Your E-mail address is only used to compute
your Gravatar and is not stored anywhere.
Comments are moderated through pull requests.