What happens if a "BEST ANSWER " is proven to be WRONG,in mathematics?

If you ask what happens on the short run I agree that "nothing" is adequate. But on the long run high buildings will start falling due to construction errors caused by mislead students having used wrong conclusions from yahoo answers. It is quite a wild scenario! So to categorize it as "nothing" is not quite adequate in that case.

Well, a lot of the time the student already knows the answer but just can't get to it, so an answer can still be worthy of best answer, even though there is a silly mistake, because the student spots the mistake but still finds the working more helpful than any of the correct answers given. This did happen to me once. I made a very silly error but gave a full and clear answer and so was chosen, although the asker did point out that I had got it wrong. Occasionally the asker is led astray by a wrong answer however, but there are generally several answers, so it's usually easy to see which are correct, particularly if they reach the same conclusion as those given by top contributors.

Nothing, and I should know, I've gotten best answer a couple of times and then spotted a dumb mistake I've made.

Generally in those (few) cases I try to contact the person who asked the question, but a lot of people disable the ability to email them through Y!A.

god bless me?

nevermind. I'm not even going to give you a logical answer.

Once you start being logical, I'll give you a logical answer.

I do not need you to type 'god bless you' in order for you to feel like you are going to a nonexistent place.

Don't go looking for logicality when believe that all human beings are incest.

(Adam and eve had to populate the earth. Adam and eve were the only humans on earth. Adam and eve reproduced. The only way there could be more generations is if the brothers and sisters had sex and reproduced... that's incest. Also, isn't that morally incorrect for Christians?? [and most other people])

then they probably need to revise their assumptions of the problem