State the homotopy lifting property of covering maps and use it to prove that the covering map \(S^n\to \mathbb {R}\mathrm {P}^n\) from the \(n\)-sphere to the real projective \(n\)-space is not nullhomotopic for any \(n\ge 1\).
Question
Math 6510 • Differentiable Manifolds
Summer 2020 • Question 7