On positive Matrices which have a Positive Smith Normal Form

Ronan Quarez (1)

1 IRMAR - Institut de Recherche Mathématique de Rennes

It is known that any symmetric matrix $M$ with entries in $\R[x]$ and which is positive semi-definite for any substitution of $x\in\R$, has a Smith normal form whose diagonal coefficients are constant sign polynomials in $\R[x]$. \par We generalize this result by considering a symmetric matrix $M$ with entries in a formally real principal domain $A$, we assume that $M$ is positive semi-definite for any ordering on $A$ and, under one additionnal hypothesis concerning non-real primes, we show that the Smith normal of $M$ is positive, up to association. Counterexamples are given when this last hypothesis is not satisfied.\par We give also a partial extension of our results to the case of Dedekind domains.

Mots clés: positive semi-definite; Smith Normal form; real spectrum

Domaines: Anneaux et algèbres [math.RA]

Ronan Quarez. On positive Matrices which have a Positive Smith Normal Form. 2009. ⟨hal-00414266⟩