What did Sofia Kovalevskaya contributions to math?
Sofya Vasilyevna Kovalevskaya, (born January 15, 1850, Moscow, Russia—died February 10, 1891, Stockholm, Sweden), mathematician and writer who made a valuable contribution to the theory of partial differential equations.
What is the Cauchy Kovalevskaya theorem used for?
First order Cauchy–Kovalevskaya theorem
This theorem is about the existence of solutions to a system of m differential equations in n dimensions when the coefficients are analytic functions. The theorem and its proof are valid for analytic functions of either real or complex variables.