Example: The set B1 is the Borel sigma-algebra of the real line, and thus contains every open interval.
Example: Consider a filled circle in the unit square. It can be constructed by a countable number of non-overlapping open rectangles (since a series of such rectangles can be defined that would cover every point in the circle but no point outside of it. Therefore it is in the smallest sigma-algebra of open subsets of the unit square.(Econterms)
Terms related to Borel Sigma-Algebra:
About.Com Resources on Borel Sigma-Algebra:None
Writing a Term Paper? Here are a few starting points for research on Borel Sigma-Algebra:
Books on Borel Sigma-Algebra:
None
Journal Articles on Borel Sigma-Algebra:
None

