Open set

Related Terms:

product topology union analytic function generic property set alexandrov topology open ball topology topological space closed set kolmogorov open rectangle hausdorff space normal space open cover antiholomorphic regular space valuation measurable function subspace topology connected borel measurable point neighborhood presheaf continuous function diffeology outer regular grothendieck topology

Noun

Definition: Informally, a set such that the target point of a movement by a small amount in any direction from any point in the set is still in the set; exemplified by a full circle without its boundary.