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Division dans l'anneau des séries formelles à croissance contrôlée. Applications

Augustin Mouze (2001)

Studia Mathematica

We consider subrings A of the ring of formal power series. They are defined by growth conditions on coefficients such as, for instance, Gevrey conditions. We prove a Weierstrass-Hironaka division theorem for such subrings. Moreover, given an ideal ℐ of A and a series f in A we prove the existence in A of a unique remainder r modulo ℐ. As a consequence, we get a new proof of the noetherianity of A.

Dualité dans les modules topologiques.

Michel Mazan (1982)

Revista Matemática Hispanoamericana

Soit I un ensembre quelconque. Si M est un sous-module quelconque de A1 et N un sous-module de Mx, α-dual de M (Mazan 1976), le dual topologique de M, muni de la topologie faible, Ts(N), est, sous certaines conditions, isomorphe topologiquement à N/M⊥. Ce résultat peut s'étendre au cas où M et N sont deux modules quelconques en dualité. Cette note étudie aussi les topologies Tℑ de M, compatibles avec la dualité et introduit la notion de topologie uniforme.

Exposé on a conjecture of Tougeron

Joseph Becker (1977)

Annales de l'institut Fourier

An algebra homomorphism of the locatized affine rings of an algebraic variety is continuous in the Krull topology of the respective local rings. It is not necessarily open or closed in the Krull topology. However, we show that the induced map on the associated analytic local rings is also open and closed in the Krull topology. To do this we prove a conjecture of Tougeron which states that if η is an analytic curve on an analytic variety V and f is a formal power series which is convergent when restricted...

Extension of the Two-Variable Pierce-Birkhoff conjecture to generalized polynomials

Charles N. Delzell (2010)

Annales de la faculté des sciences de Toulouse Mathématiques

Let h : n be a continuous, piecewise-polynomial function. The Pierce-Birkhoff conjecture (1956) is that any such h is representable in the form sup i inf j f i j , for some finite collection of polynomials f i j [ x 1 , ... , x n ] . (A simple example is h ( x 1 ) = | x 1 | = sup { x 1 , - x 1 } .) In 1984, L. Mahé and, independently, G. Efroymson, proved this for n 2 ; it remains open for n 3 . In this paper we prove an analogous result for “generalized polynomials” (also known as signomials), i.e., where the exponents are allowed to be arbitrary real numbers, and not just natural numbers;...

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