One of the founders of elliptical theory with his four theta functions, his symbol in number theory is a product of Legendre symbols, and his name is also used for hypergeometric polynomials.  
His conjecture says that if the determinant of the derivative of a polynomial mapping is one, its inverse exists and is a polynomial.  One of the founders of elliptical theory with his four theta functions, his symbol in number theory is a product of Legendre symbols, and his name is also used for hypergeometric polynomials.  FTP, identify this German whose identity for Lie algebras is a weaker version of associativity and whose matrix consists of the first partial derivatives of a vector-valued function.
His conjecture says that if the determinant of the derivative of a polynomial mapping is one, its inverse exists and is a polynomial.  
Karl Jacobi