Complexity of the class of Peano functions
K. Omiljanowski, S. Solecki, J. Zielinski (2000)
Colloquium Mathematicae
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We evaluate the descriptive set theoretic complexity of the space of continuous surjections from to .
K. Omiljanowski, S. Solecki, J. Zielinski (2000)
Colloquium Mathematicae
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We evaluate the descriptive set theoretic complexity of the space of continuous surjections from to .
K. Adžievski (1986)
Matematički Vesnik
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Robert Deville, Vladimir Fonf, Petr Hájek (1996)
Studia Mathematica
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Eberhard Gerlach (1968)
Annales de l'institut Fourier
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On démontre que, dans les espaces fonctionnels propres de Hilbert (avec un noyau reproduisant), formés de fonctions analytiques de variables dans un domaine , pour tout opérateur auto-adjoint, les fonctions propres généralisées sont des fonctions réelles-analytiques dans .
D. Przeworska-Rolewicz
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Let X be a linear space. Consider a linear equation(*) P(D)x = y, where y ∈ E ⊂ X,with a right invertible operator D ∈ L(X) and, in general, operator coefficients. The main purpose of this paper is to characterize those subspaces E ⊂ X for which all solutions of (*) belong to E (provided that they exist). This leads, even in the classical case of ordinary differential equations with scalar coefficients, to a new class of -functions, which properly contains the classes of analytic functions...
José F. Fernando, Jesús M. Ruiz (2005)
Bulletin de la Société Mathématique de France
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We show that (i) the Pythagoras number of a real analytic set germ is the supremum of the Pythagoras numbers of the curve germs it contains, and (ii) every real analytic curve germ is contained in a real analytic surface germ with the same Pythagoras number (or Pythagoras number if the curve is Pythagorean). This gives new examples and counterexamples concerning sums of squares and positive semidefinite analytic function germs.
Augustin Fruchard, Reinhard Schäfke (2003)
Annales de l’institut Fourier
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We consider a singularity perturbed nonlinear differential equation which we suppose real analytic for near some interval and small , . We furthermore suppose that 0 is a turning point, namely that is positive if . We prove that the existence of nicely behaved (as ) local (at ) or global, real analytic or solutions is equivalent to the existence of a formal series solution with analytic at . The main tool of a proof is a new “principle of analytic continuation” for...
Oleg Okunev (1993)
Commentationes Mathematicae Universitatis Carolinae
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We prove that a cosmic space (= a Tychonoff space with a countable network) is analytic if it is an image of a -analytic space under a measurable mapping. We also obtain characterizations of analyticity and -compactness in cosmic spaces in terms of metrizable continuous images. As an application, we show that if is a separable metrizable space and is its dense subspace then the space of restricted continuous functions is analytic iff it is a -space iff is -compact. ...
Sameer Chavan (2010)
Colloquium Mathematicae
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Let denote a complex, infinite-dimensional, separable Hilbert space, and for any such Hilbert space , let () denote the algebra of bounded linear operators on . We show that for any co-analytic, right-invertible T in (), αT is hypercyclic for every complex α with , where . In particular, every co-analytic, right-invertible T in () is supercyclic.