Abstract<title> SUMMARY </title>We have gathered here twenty-six writings from the correspondence of Giuseppe Peano, as well as letters by Alexander Macfarlane and Alexander Ziwet.Peano's letters were addressed to Ernesto Cesaro, an important member of the great Italian school of mathematics founded in the second half of the Nineteenth century. In these writings, Peano discusses various topics: Infinitesimal calculus and Barycentric calculus, the «Rivista di Matematica» and the «Formulario» of which he was editor; didactics and a question about Actuarial mathematics. Some of the writings are confidential in nature: in one letter, Peano proposes exchanging his professorial chair with Cesaro's, and hence transferring from Turin to Naples.The letters written by Macfarlane and Ziwet were sent to Peano; they contain, at the request of Cesaro, information concerning university chairs and the cost of living in the United States.
Total Differentiability and Monogenicity for Functions in Algebras of Order 4
