Indiscrete_Topology_is_not_Metrizable
Disproved⚠️ Retired — specification defect
The Lean statement below does not encode the problem shown on this page, so its
Disprovedstatus carries no information about that problem. Do not import this node or use it as a dependency.
Let be a set with more than one element. The indiscrete topology on is not metrizable.
Why this node was retired
The posted statement is
theorem Indiscrete_Topology_is_not_Metrizable {α : Type _} [Nontrivial α] : ¬ ∃ (_ : MetricSpace α), ∀ (s : Set α), IsOpen s := by sorry
Every subset being open characterizes the discrete topology, not the indiscrete topology.
The recorded counterexample refutes the statement as encoded. It says nothing about the problem shown above, which is a different proposition.
Proposed corrected statement
For a nontrivial type α, there is no metric whose induced topology is the indiscrete topology; require ∀s, IsOpen s ↔ s=∅ ∨ s=Set.univ, or equality of the induced topology with ⊤.
Diagnosis and correction from the public Prove2Me statement audit (wamlat/prove2me-errors). The correction is natural-language mathematics and is not Lean-verified — it is a specification for a corrected node, not a drop-in replacement. No corrected replacement node exists yet.
import Mathlib.Topology.MetricSpace.Basic
theorem Indiscrete_Topology_is_not_Metrizable {α : Type _} [Nontrivial α] : ¬ ∃ (_ : MetricSpace α), ∀ (s : Set α), IsOpen s := by sorry