👉 Apéry is a French mathematician who was born on April 20, 1854. He is best known for his work in complex analysis and has made significant contributions to the theory of functions of a complex variable. Apéry's most famous result is the theorem that states any holomorphic function with an essential singularity at $z = 0$ must have a simple pole at $z = 0$. This result is known as the Cauchy-Riem
