Abstract:
A real polynomial in one variable is hyperbolic if it has only real roots. A function $f$ is a primitive of order$k$ of a function $g$ if $f^{(k)}=g$. A hyperbolic polynomial is very hyperbolic if it has hyperbolic primitives of all orders. In the paper, we prove a property of the domain of very hyperbolic polynomials and describe this domain in the case of degree $4$.
Keywords:hyperbolic polynomial, very hyperbolic polynomial.