I recently answered my own question but my answer was deleted promptly for being 'additional information' rather than an answer. Here's the question:
And my answer was:
They are equivalent.
(Thanks to Did for the comment.)
One of the reviewers was kind enough to comment on my answer and said:
Please use the edit link on your question to add additional information. The Post Answer button should be used only for complete answers to the question.
From my perspective, I'm pretty sure the contents of my answer were about as direct an answer to the question as is possible. I don't see how it could be construed as mere 'additional information'. I can understand if Did should get the credit for the response, but given that he only posted as a comment I thought I would formalise it into an answer.
Why was the answer deleted?