I'm guessing this is in reference to a famous math problem, open for quite a long time, posed in the paper "Can One Hear the Shape of a Drum?" by Mark Kac. htt

I'm guessing this is in reference to a famous math problem, open for quite a long time, posed in the paper "Can One Hear the Shape of a Drum?" by Mark Kac. https://en.wikipedia.org/wiki/Hearing_the_shape_of_a_drum https://en.wikipedia.org/wiki/Hearing_the_shape_of_a_drum https://www.math.ucdavis.edu/~hunter/m207b/kac.pdf https://www.math.ucdavis.edu/~hunter/m207b/kac.pdf