Sur le spectre d'un polynôme à plusieurs variables
Nous donnons les démonstrations détaillées des résultats énoncés dans une note de même titre (C. R. Acad. Sci., Paris, Ser. I 303 (1986), 539–542).Ces résultats concernent le nombre et la position des zéros réels des polynômes de Bernoulli.
Let K be an ordered field. The set X(K) of its orderings can be topologized to make it a Boolean space. Moreover, it has been shown by Craven that for any Boolean space Y there exists a field K such that X(K) is homeomorphic to Y. Becker's higher level ordering is a generalization of the usual concept of ordering. In a similar way to the case of ordinary orderings one can define a topology on the space of orderings of fixed exact level. We show that it need not be Boolean. However, our main theorem...
The algebraically closed field of Nash functions is introduced. It is shown that this field is an algebraic closure of the field of rational functions in several variables. We give conditions for the irreducibility of polynomials with Nash coefficients, a description of factors of a polynomial over the field of Nash functions and a theorem on continuity of factors.
Let be the Mahler measure of an algebraic number , and be an open subset of . Then its Lehmer constant is inf , the infimum being over all non-zero non-cyclotomic lying with its conjugates outside . We evaluate when is any annulus centered at . We do the same for a variant of , which we call the transfinite Lehmer constant .Also, we prove the converse to Langevin’s Theorem, which states that if contains a point of modulus . We prove the corresponding result for .
We prove that the study of the Łojasiewicz exponent at infinity of overdetermined polynomial mappings , m > n, can be reduced to the one when m = n.