A region is an open connected set (sometimes also called a domain).
Region
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Cite this as:
Weisstein, Eric W. "Region." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Region.html
A region is an open connected set (sometimes also called a domain).
Weisstein, Eric W. "Region." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Region.html