I have asked around year ago a question something like
"Prove that any compact, connected, simply connected, semisimple Lie group is $SU(2)$"
and want to read its answer but now I can't find it. I know that it has been commented/answered by @QiaochuYuan and/or @jasonDevito. I have tried this query without success. Now I guess it has been deleted but not by me. Is that possible?