I posted a question on mathoverflow. It was regarding a counter example that I had found. Later I realized that I should not have done that and deleted it. I am writing a research paper on how I constructed the example. Do I still have rights for my example?
You can’t copyright an idea, only a text. Posting something here has a copyright effect on the specific text you post, but a paper with the same ideas (but presumably a lot more exposition) would not be affected.