The GATE Grind

GATE 2024 MA – Question 41

Topology · Connectedness and Compactness · 2 marks · Multiple choice

X=ℝ/ℤ has the quotient topology from usual ℝ. I:X is compact. II:Removing any one point leaves X connected. Choose truth values.

  1. Both I and II true
  2. I true, II false
  3. I false, II true
  4. Both false

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (A) Both I and II true

Explanation

The map t↦e^(2πit) identifies the quotient with the unit circle. It is compact as the image of [0,1]. Removing one circle point gives a space homeomorphic to an open interval, hence connected. **Both true, A**.

More Connectedness and Compactness questions

All Connectedness and Compactness questions →