theorem
PiBase.TopologicalSpace.indiscrete_iff_isOpen_iff_empty_or_univ
(X : Type u)
[TopologicalSpace X]
:
A space is indiscrete iff all open sets are either the empty space or the entire space.
@[simp]
Every topological space is as least as fine as the indiscrete topology.
@[simp]
Every topological space is as least as coarse as the indiscrete topology.
theorem
PiBase.Homeomorph.indiscreteTopology
{X : Type u_1}
{Y : Type u_2}
[TopologicalSpace X]
[TopologicalSpace Y]
[h : IndiscreteTopology X]
(f : X ≃ₜ Y)
: