Are SU(2) and SO(3) Groups Really Isomorphic?

[ber70]

I have not seen why SU(2) and SO(3) groups are isomorphic?

 

[D H]

They aren't isomorphic. SU(2) is a double cover of SO(3).

 

[mrbohn1]

Their Lie algebras are isomorphic, and they are locally isomorphic...but D H is right - they aren't isomorphic!