Equivalently, it is a relatively open subset of its closure.

Let 'D' be an open subset of the real line.

In addition, the transition maps between these open subsets are required to be holomorphic.

In g they form an open and dense subset.

B is the collection of all open subsets of .

Let E be an open subset of R, called the edge.

Let D be an open subset in R which does not contain the origin 0.

Let be an open subset of , and be a measure space.

It follows that, in the case where their number is finite, each component is also an open subset.

Trivially, any open subset of a topological space is a G set.