Exoo–Ismailescu: The Final Word on Problem 15.4
摘要
On September 20, 2016, I received an e-mail from Dan Ismailescu:The e-mail below from Ismailescu, copied to his coauthor Geoffrey Exoo, was in fact dated a whole 8 months earlier, on January 26, 2016, and read as follows:I sent my reply to the authors on September 25, 2016, after an extensive but futile search of my inbox:In 10 min, I had the essay in my hands and dove into it. It was a treasure. My response was immediate:Geoffrey replied: