1) blog.computationalcomplexity.org/2016/07/solution-to-alice-bob-box-problem.html Solution to the Alice-Bob-Box problem. July 18, 2016 Posted by GASARCH Computational Complexity (抜粋) Peter Winkler told me this problem at the Joel Spencer 70th Bday conference. He got it from Sergui Hart who does not claim to be the inventor of it. (抜粋おわり)