We generalize the Malgrange preparation theorem to matrix valued functions $F(t,x)\in C^{\infty }(\mathbf{R}\times {\mathbf{R}}^n)$ satisfying the condition that $t\mapsto \det F(t,0)$ vanishes to finite order at $t=0$. Then we can factor $F(t,x)=C(t,x)P(t,x)$ near (0,0), where $C(t,x)\in C^{\infty }$ is inversible and $P(t,x)$ is polynomial function of $t$ depending $C^{\infty }$ on $x$. The preparation is (essentially) unique, up to functions vanishing to infinite order at $x=0$, if we impose some additional conditions on $P(t,x)$. We also have a generalization of the division theorem, and analytic versions generalizing the Weierstrass preparation...

On donne une variante du principe de la phase stationnaire, où l’intégrale est remplacée par une sommation sur le réseau cubique de maille égale à l’unité de phase.

Considering jets, or functions, belonging to some strongly non-quasianalytic Carleman class on compact subsets of ${ℝ}^n$, we extend them to the whole space with a loss of Carleman regularity. This loss is related to geometric conditions refining Łojasiewicz’s “regular separation” or Whitney’s “property (P)”.