Real radiciality and monoreal extensions

Abstract

We study irreducible polynomials admitting a single real root in any real closed field extension of the base field, called monoreal polynomials. We show some stability properties satisfied by the induced monoreal field extensions, and define the monoreal closure of a field. We make the link with a notion of real radiciality for ring extensions, and an injectivity property at the real spectrum level. We end with a geometric application, showing that injectivity implies surjectivity for the real spectrum mapping, under certain assumptions.