The question [How the idea of adjoint matrix has been designed?][1] isn't great, but isn't awful, and [these][2] [two][3] answers have been posted (and upvoted) on G+ rather than as answers, which is dumb. Let's reopen the question so that the answers can be added.

As an aside, the fact that Allen Knutson basically said "this is **going to be** closed, so I won't contribute my awesome answer here" says something terrible about how closing is treated by MO participants. The last MO board meeting included a discussion of how to address the problem of high-rep close-happy users making the site hostile towards grad students and advanced undergrads, who we *really want* to be comfortable posting questions and answers, but I don't think there was any publicly visible action on it :-/.

It also bums me out that Allen and François both have the ability to edit the question to improve it, but didn't, even though they were willing to put in the effort to post answers.

  [1]: http://mathoverflow.net/questions/220259/how-the-idea-of-adjoint-matrix-has-been-designed
  [2]: https://plus.google.com/+AllenKnutson/posts/LgLxgxsXNAT
  [3]: https://plus.google.com/+FrancoisDorais/posts/C6SBgvj5v8e