The sleeping beauty problem is a well known problem in probability theory, see e.g. https://en.wikipedia.org/wiki/Sleeping_Beauty_problem http://allendowney.blogspot.hr/2015/06/the-sleeping-beauty-problem.html https://www.quantamagazine.org/solution-sleeping-beautys-dilemma-20160129 or just google. Allegedly, there are many "thirders" who think that the correct answer is 1/3, but also many "halfers" who think that the correct answer is 1/2. For me, it is quite obvious that the correct answer is 1/3. Is there anybody here who is convinced that the correct answer is 1/2? If you are one of them, what is your argument for 1/2?