A sigma-algebra which is related to the topology of a set. The Borel -algebra is defined to be the sigma-algebra generated by the open sets (or equivalently, by the closed sets).

# Borel Sigma-Algebra

## See also

Borel Measure, Sigma-Algebra## Explore with Wolfram|Alpha

## Cite this as:

Weisstein, Eric W. "Borel Sigma-Algebra."
From *MathWorld*--A Wolfram Web Resource. https://mathworld.wolfram.com/BorelSigma-Algebra.html