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K-subanalytic rectilinearization and uniformization

Artur Piękosz (2003)

Open Mathematics

We prove rectilinearization and uniformization theorems for K-subanalytic (∝anK-definable) sets and functions using the Lion-Rolin formula. Parallel reasoning gives standard results for the subanalytic case.

Local analytic rings

Jorge C. Zilber (1990)

Cahiers de Topologie et Géométrie Différentielle Catégoriques

On gradients of functions definable in o-minimal structures

Krzysztof Kurdyka (1998)

Annales de l'institut Fourier

We prove the o-minimal generalization of the Łojasiewicz inequality grad f | f | α , with α < 1 , in a neighborhood of a , where f is real analytic at a and f ( a ) = 0 . We deduce, as in the analytic case, that trajectories of the gradient of a function definable in an o-minimal structure are of uniformly bounded length. We obtain also that the gradient flow gives a retraction onto levels of such functions.

On some noetherian rings of C germs on a real closed field

Abdelhafed Elkhadiri (2011)

Annales Polonici Mathematici

Let R be a real closed field, and denote by R , n the ring of germs, at the origin of Rⁿ, of C functions in a neighborhood of 0 ∈ Rⁿ. For each n ∈ ℕ, we construct a quasianalytic subring R , n R , n with some natural properties. We prove that, for each n ∈ ℕ, R , n is a noetherian ring and if R = ℝ (the field of real numbers), then , n = , where ₙ is the ring of germs, at the origin of ℝⁿ, of real analytic functions. Finally, we prove the Real Nullstellensatz and solve Hilbert’s 17th Problem for the ring R , n .

On the rings of formal solutions of polynomial differential equations

Maria-Angeles Zurro (1998)

Banach Center Publications

The paper establishes the basic algebraic theory for the Gevrey rings. We prove the Hensel lemma, the Artin approximation theorem and the Weierstrass-Hironaka division theorem for them. We introduce a family of norms and we look at them as a family of analytic functions defined on some semialgebraic sets. This allows us to study the analytic and algebraic properties of this rings.

Preparation theorems for matrix valued functions

Nils Dencker (1993)

Annales de l'institut Fourier

We generalize the Malgrange preparation theorem to matrix valued functions F ( t , x ) C ( R × R n ) satisfying the condition that t 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 ) C is inversible and P ( t , x ) is polynomial function of t depending C 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...

Radially symmetric plurisubharmonic functions

Per Åhag, Rafał Czyż, Leif Persson (2012)

Annales Polonici Mathematici

In this note we consider radially symmetric plurisubharmonic functions and the complex Monge-Ampère operator. We prove among other things a complete characterization of unitary invariant measures for which there exists a solution of the complex Monge-Ampère equation in the set of radially symmetric plurisubharmonic functions. Furthermore, we prove in contrast to the general case that the complex Monge-Ampère operator is continuous on the set of radially symmetric plurisubharmonic functions. Finally...

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