The Stone-Cech Compactification

Mike Stannett 📧

May 27, 2024

This is a development version of this entry. It might change over time and is not stable. Please refer to release versions for citations.


Building on parts of HOL-Analysis, we provide mathematical components for work on the Stone-Cech compactification. The main concepts covered are: $C^*$-embedding, weak topologies and compactification, focusing in particular on the Stone-Cech compactification of an arbitrary Tychonov space $X$. Using traditional topological proof strategies we define the evaluation and projection functions for product spaces, and show that product spaces carry the weak topology induced by their projections whenever those projections separate points both from each other and from closed sets. In particular, we show that the evaluation map from an arbitrary Tychonov space $X$ into $\beta{X}$ is a dense $C^*$-embedding, and then verify the Stone-Cech Extension Property: any continuous map from $X$ to a compact Hausdorff space $K$ extends uniquely to a continuous map from $\beta{X}$ to $K$. Many of the proofs given here derive from those of Willard (General Topology, 1970, Addison-Wesley) and Walker (The Stone-Cech Compactification, 1974, Springer-Verlag).


BSD License


Session Stone_Cech