Second Countable Space: Topology, Topological Space, Base (Topology), Countable, Open Set

Trivial Topology: Topology, Topological Space, Open Set

Whitney Embedding Theorem: Mathematics, Differential Topology, Differentiable Manifold, Hausdorff Space, Second Countable

Suspension (Topology): Topology, Topological Space, Quotient Product Topology

Neighbourhood (mathematics): (mathematics), Topology, Mathematics, Topological Space, Open Set, Interior (topology)