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  1. Marianne Morillon (2012). Some Consequences of Rado's Selection Lemma. Archive for Mathematical Logic 51 (7-8):739-749.
    We prove in set theory without the Axiom of Choice, that Rado’s selection lemma ( ${\mathbf{RL}}$ ) implies the Hahn-Banach axiom. We also prove that ${\mathbf{RL}}$ is equivalent to several consequences of the Tychonov theorem for compact Hausdorff spaces: in particular, ${\mathbf{RL}}$ implies that every filter on a well orderable set is included in a ultrafilter. In set theory with atoms, the “Multiple Choice” axiom implies ${\mathbf{RL}}$.
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  2. Marianne Morillon (2010). Notions of Compactness for Special Subsets of ℝ I and Some Weak Forms of the Axiom of Choice. Journal of Symbolic Logic 75 (1):255-268.
    We work in set-theory without choice ZF. A set is Countable if it is finite or equipotent with ${\Bbb N}$ . Given a closed subset F of [0, 1] I which is a bounded subset of $\ell ^{1}(I)$ (resp. such that $F\subseteq c_{0}(I)$ ), we show that the countable axiom of choice for finite sets, (resp. the countable axiom of choice AC N ) implies that F is compact. This enhances previous results where AC N (resp. the axiom of Dependent (...)
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  3. Marianne Morillon (2005). James Sequences and Dependent Choices. Mathematical Logic Quarterly 51 (2):171-186.
    We prove James's sequential characterization of reflexivity in set-theory ZF + DC, where DC is the axiom of Dependent Choices. In turn, James's criterion implies that every infinite set is Dedekind-infinite, whence it is not provable in ZF. Our proof in ZF + DC of James' criterion leads us to various notions of reflexivity which are equivalent in ZFC but are not equivalent in ZF. We also show that the weak compactness of the closed unit ball of a reflexive space (...)
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  4. Christian Delhommé & Marianne Morillon (1999). Dependent Choices and Weak Compactness. Notre Dame Journal of Formal Logic 40 (4):568-573.
    We work in set theory without the Axiom of Choice ZF. We prove that the Principle of Dependent Choices (DC) implies that the closed unit ball of a uniformly convex Banach space is weakly compact and, in particular, that the closed unit ball of a Hilbert space is weakly compact. These statements are not provable in ZF and the latter statement does not imply DC. Furthermore, DC does not imply that the closed unit ball of a reflexive space is weakly (...)
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  5. Juliette Dodu & Marianne Morillon (1999). The Hahn-Banach Property and the Axiom of Choice. Mathematical Logic Quarterly 45 (3):299-314.
    We work in set theory ZF without axiom of choice. Though the Hahn-Banach theorem cannot be proved in ZF, we prove that every Gateaux-differentiable uniformly convex Banach space E satisfies the following continuous Hahn-Banach property: if p is a continuous sublinear functional on E, if F is a subspace of E, and if f: F → ℝ is a linear functional such that f ≤ p|F then there exists a linear functional g : E → ℝ such that g extends (...)
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  6. Marianne Morillon (1991). Extreme Choices on Complete Lexicographic Orders. Zeitschrift fur mathematische Logik und Grundlagen der Mathematik 37 (23‐24):353-355.
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  7. Labib Haddad & Marianne Morillon (1990). L'axiome de Normalité Pour Les Espaces Totalement Ordonnés. Journal of Symbolic Logic 55 (1):277-283.
    We show that the following property (LN) holds in the basic Cohen model as sketched by Jech: The order topology of any linearly ordered set is normal. This proves the independence of the axiom of choice from LN in ZF, and thus settles a question raised by G. Birkhoff (1940) which was partly answered by van Douwen (1985).
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