I think there's a precedence for it too. I believe George Dantzig's doctoral advisor offered to accept the solutions to a homework set as a thesis since it solved major open statistical problems.
"During his first year as a doctoral student at the University of California-Berkeley, Dantzig arrived late to the class of Jerzy Neyman, one of the great founders of modern statistics. On the blackboard were two problems that Dantzig assumed to be homework.
"A few days later I apologized to Neyman for taking so long to do the homework—the problems seemed harder to do than usual," Dantzig once recalled. It turned out the conundrums, which Dantzig solved, were two famous unsolved problems in statistics."
https://news.stanford.edu/news/2005/may25/dantzigobit-052505...