Definitions Found:
A family of open subsets of an abstract space such that the union and the intersection of any two of them are members of the family, and that includes the space itself and the empty set
- topologyA family of open subsets of an abstract space such that the union and the intersection of any two of them are members of the family, and that includes the space itself and the empty set
- topologiesA family of open subsets of an abstract space such that the union and the intersection of any two of them are members of the family, and that includes the space itself and the empty set