The classic middle-thirds Cantor Set being a topologically set is one of the easiest counter examples to the above misconception that the sets need to be continuous themselves.
Being able to define a neighborhood or a concept of closeness is required, but the concept of distance is not required.
If you can define a distance a topological space is a metric space
If it is locally euclidean it may be a manifold.
Really the union and finite intersection of subsets is the formal way of showing something is a topological space. Too har do describe here but that is where the concept of continuity arises.
Comments
The classic middle-thirds Cantor Set being a topologically set is one of the easiest counter examples to the above misconception that the sets need to be continuous themselves.
Being able to define a neighborhood or a concept of closeness is required, but the concept of distance is not required.
If you can define a distance a topological space is a metric space
If it is locally euclidean it may be a manifold.
Really the union and finite intersection of subsets is the formal way of showing something is a topological space. Too har do describe here but that is where the concept of continuity arises.