Reputation
12,894
Next privilege 15,000 Rep.
Protect questions
Badges
5 31 48
Newest
 Nice Answer
Impact
~104k people reached

Feb
15
awarded  Nice Answer
Feb
13
awarded  Yearling
Feb
13
awarded  Good Answer
Nov
12
awarded  Enlightened
Nov
12
awarded  Nice Answer
Oct
29
awarded  Enlightened
Oct
29
awarded  Nice Answer
Aug
29
revised How to show $[\omega]=0$ implies $[\omega^n]=0$?
added 27 characters in body
Aug
12
awarded  Enlightened
Aug
12
awarded  Nice Answer
Aug
8
comment Example of a pair of non-cobordant manifolds
The cone on $\Bbb C P^2$ is not a topological manifold. In fact, the cone on any space $X$ that does not have the same integral homology as a sphere cannot possibly be a manifold, because for such spaces we have $\tilde{H}_\ast(X, X - \text{cone pt}; \Bbb Z) \not \cong \Bbb Z$.
Feb
23
awarded  Enlightened
Feb
23
awarded  Nice Answer
Feb
13
awarded  Yearling
Feb
8
awarded  Nice Answer
Dec
20
awarded  Constituent
Dec
17
awarded  Good Answer
Dec
10
awarded  Caucus
Sep
30
awarded  Explainer
Sep
13
awarded  Good Answer