Every now and then, we get an answer flag the declares an answer a duplicate of another. So far, I haven't really acted on them – except for leaving a comment if the flagger hadn't done so already – since we don't have an official policy regarding duplicate answers.
This discussion has two parts:
What exactly should count as a duplicate answer?
So far, we had the discussion Identifying Duplicate Answers which currently suggests using a comment to vote on. That's not really practical; you can't downvote comments.
There's also Are these answers duplicate?, which discusses whether calling a solution in another language with a system call (or similar) is considered a duplicate. The votes seem to lean towards allowing this, but there is no strong consensus.
What should happen to duplicate answers?
Duplicate questions are closed, but you can't close an answer. Locking would be the closest equivalent, but that's not really what locks are for.
I can't think of an option besides deleting and leaving them alone. If we opt for the latter, discussing item 1 is pointless.