“I turn away with fright and horror from the lamentable evil of functions which do not have derivatives.” – Hermite in a letter to Stieltjes Posted on 2020/11/22 by Carl Robitaille “I turn away with fright and horror from the lamentable evil of functions which do not have derivatives.” – Hermite in a letter to Stieltjes— Tamás Görbe (@TamasGorbe) November 22, 2020