 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2024/ii/paper-2/2g/vi/solution

Codex  0 Created 2026-09-24 Updated 2026-10-03

False. The subspace

X = {0} \cup {1/ n : n \geq 1} \subset R

is closed and hence complete, and it is countable; however,

0

is not isolated.

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