Displaying similar documents to “Localization of biholomorphisms for real hyperquadrics in C 3 : a computational approach”

Composition operators on Banach spaces of formal power series

B. Yousefi, S. Jahedi (2003)

Bollettino dell'Unione Matematica Italiana

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Let β n n = 0 be a sequence of positive numbers and 1 p < . We consider the space H p β of all power series f z = n = 0 f n z n such that n = 0 f n p β n p < . Suppose that 1 p + 1 q = 1 and n = 1 n q j β n q = for some nonnegative integer j . We show that if C φ is compact on H p β , then the non-tangential limit of φ j + 1 has modulus greater than one at each boundary point of the open unit disc. Also we show that if C φ is Fredholm on H p β , then φ must be an automorphism of the open unit disc.

The Poincaré lemma and local embeddability

Judith Brinkschulte, C. Denson Hill, Mauro Nacinovich (2003)

Bollettino dell'Unione Matematica Italiana

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For pseudocomplex abstract C R manifolds, the validity of the Poincaré Lemma for 0 , 1 forms implies local embeddability in C N . The two properties are equivalent for hypersurfaces of real dimension 5 . As a corollary we obtain a criterion for the non validity of the Poicaré Lemma for 0 , 1 forms for a large class of abstract C R manifolds of C R codimension larger than one.

On the fiber of the compound of a real analytic function by a projection

Alain Jacquemard (1999)

Bollettino dell'Unione Matematica Italiana

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Sia f : R m R k con m k 1 una funzione analitica. Se il luogo critico di f è compatto, esiste una fibrazione C localmente triviale associata ai livelli f . Supponiamo k 2 e sia π k la proiezione x 1 , , x k - 1 , x k x 1 , , x k - 1 , x k . Sotto una condizione sul luogo critico di f ~ = π k f esiste anche una fibrazione C localmente triviale associata ai livelli di f ~ . Siano F e F ~ le fibre rispettitive, e I l'intervallo unità reale. Dimostriamo qui che F ~ è omeomorfa al prodotto F × I . Nel caso di polinomi studiamo criteri effettivi. Diamo inoltre un'applicazione...

Schwartz kernels on the Heisenberg group

Alessandro Veneruso (2003)

Bollettino dell'Unione Matematica Italiana

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Let H n be the Heisenberg group of dimension 2 n + 1 . Let L 1 , , L n be the partial sub-Laplacians on H n and T the central element of the Lie algebra of H n . We prove that the kernel of the operator m L 1 , , L n , - i T is in the Schwartz space S H n if m S R n + 1 . We prove also that the kernel of the operator h L 1 , , L n is in S H n if h S R n and that the kernel of the operator g L , - i T is in S H n if g S R 2 . Here L = L 1 + + L n is the Kohn-Laplacian on H n .