On the Jordan model operators
Hari Bercovici (1977)
Studia Mathematica
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Hari Bercovici (1977)
Studia Mathematica
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Chi-Kwong Li, Nung-Sing Sze (2006)
Studia Mathematica
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Let V be the C*-algebra B(H) of bounded linear operators acting on the Hilbert space H, or the Jordan algebra S(H) of self-adjoint operators in B(H). For a fixed sequence (i₁, ..., iₘ) with i₁, ..., iₘ ∈ 1, ..., k, define a product of by . This includes the usual product and the Jordan triple product A*B = ABA as special cases. Denote the numerical range of A ∈ V by W(A) = (Ax,x): x ∈ H, (x,x) = 1. If there is a unitary operator U and a scalar μ satisfying such that ϕ: V → V has...
M. Laczkovich (2003)
Fundamenta Mathematicae
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Let denote the isometry group of . We prove that if G is a paradoxical subgroup of then there exist G-equidecomposable Jordan domains with piecewise smooth boundaries and having different volumes. On the other hand, we construct a system of Jordan domains with differentiable boundaries and of the same volume such that has the cardinality of the continuum, and for every amenable subgroup G of , the elements of are not G-equidecomposable; moreover, their interiors are not G-equidecomposable...
Jinchuan Hou, Chi-Kwong Li, Ngai-Ching Wong (2008)
Studia Mathematica
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Let ₁, ₂ be (not necessarily unital or closed) standard operator algebras on locally convex spaces X₁, X₂, respectively. For k ≥ 2, consider different products on elements in , which covers the usual product and the Jordan triple product T₁ ∗ T₂ = T₂T₁T₂. Let Φ: ₁ → ₂ be a (not necessarily linear) map satisfying whenever any one of ’s has rank at most one. It is shown that if the range of Φ contains all rank one and rank two operators then Φ must be a Jordan isomorphism multiplied...
Nazar Arakelian, Herivelto Borges (2015)
Acta Arithmetica
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For each integer s ≥ 1, we present a family of curves that are -Frobenius nonclassical with respect to the linear system of plane curves of degree s. In the case s=2, we give necessary and sufficient conditions for such curves to be -Frobenius nonclassical with respect to the linear system of conics. In the -Frobenius nonclassical cases, we determine the exact number of -rational points. In the remaining cases, an upper bound for the number of -rational points will follow from Stöhr-Voloch...
Marcell Gaál (2020)
Commentationes Mathematicae Universitatis Carolinae
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The binary operation , called Jordan triple product, and its variants (such as e.g. the sequential product or the inverted Jordan triple product ) appear in several branches of operator theory and matrix analysis. In this paper we briefly survey some analytic and algebraic properties of these operations, and investigate their intimate connection to Thompson type isometries in different operator algebras.
Mohammad Ashraf, Nazia Parveen, Bilal Ahmad Wani (2017)
Communications in Mathematics
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Let be the triangular algebra consisting of unital algebras and over a commutative ring with identity and be a unital -bimodule. An additive subgroup of is said to be a Lie ideal of if . A non-central square closed Lie ideal of is known as an admissible Lie ideal. The main result of the present paper states that under certain restrictions on , every generalized Jordan triple higher derivation of into is a generalized higher derivation of into . ...
Mohammad Ashraf, Mohammad Aslam Siddeeque, Abbas Hussain Shikeh (2024)
Czechoslovak Mathematical Journal
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Let be a noncommutative prime ring equipped with an involution ‘’, and let be the maximal symmetric ring of quotients of . Consider the additive maps and . We prove the following under some inevitable torsion restrictions. (a) If and are fixed positive integers such that for all and for all , then . (b) If for all , then . Furthermore, we characterize Jordan left -centralizers in semiprime rings admitting an anti-automorphism . As applications, we find the...
Yuri Bilu, Pierre Parent, Marusia Rebolledo (2013)
Annales de l’institut Fourier
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Using the recent isogeny bounds due to Gaudron and Rémond we obtain the triviality of , for and a prime number exceeding . This includes the case of the curves . We then prove, with the help of computer calculations, that the same holds true for in the range , . The combination of those results completes the qualitative study of rational points on undertook in our previous work, with the only exception of .
Michael Hutchings (2002)
Journal of the European Mathematical Society
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Let be a surface with a symplectic form, let be a symplectomorphism of , and let be the mapping torus of . We show that the dimensions of moduli spaces of embedded pseudoholomorphic curves in , with cylindrical ends asymptotic to periodic orbits of or multiple covers thereof, are bounded from above by an additive relative index. We deduce some compactness results for these moduli spaces. This paper establishes some of the foundations for a program with Michael Thaddeus, to...
Michael Friedman, Rebecca Lehman, Maxim Leyenson, Mina Teicher (2012)
Journal of the European Mathematical Society
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The classical Segre theory gives a necessary and sufficient condition for a plane curve to be a branch curve of a (generic) projection of a smooth surface in . We generalize this result for smooth surfaces in a projective space of any dimension in the following way: given two plane curves, and , we give a necessary and sufficient condition for to be the branch curve of a surface in and to be the image of the double curve of a -model of . In the classical Segre theory, a...
Nikolay Nikolov, László Pyber (2011)
Journal of the European Mathematical Society
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We first note that a result of Gowers on product-free sets in groups has an unexpected consequence: If is the minimal degree of a representation of the finite group , then for every subset of with we have . We use this to obtain improved versions of recent deep theorems of Helfgott and of Shalev concerning product decompositions of finite simple groups, with much simpler proofs. On the other hand, we prove a version of Jordan’s theorem which implies that if , then has a...
G. Letac, J. Wesołowski (2011)
Bulletin de la Société Mathématique de France
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If the space of quadratic forms in is splitted in a direct sum and if and are independent random variables of , assume that there exist a real number such that and real distinct numbers such that for any in We prove that this happens only when , when can be structured in a Euclidean Jordan algebra and when and have Wishart distributions corresponding to this structure.
Amir Akbary, Adam Tyler Felix (2015)
Acta Arithmetica
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We prove several results regarding some invariants of elliptic curves on average over the family of all elliptic curves inside a box of sides A and B. As an example, let E be an elliptic curve defined over ℚ and p be a prime of good reduction for E. Let be the exponent of the group of rational points of the reduction modulo p of E over the finite field . Let be the family of elliptic curves , where |a| ≤ A and |b| ≤ B. We prove that, for any c > 1 and k∈ ℕ, )as x → ∞, as long...
Tomas Edlund (2004)
Annales Polonici Mathematici
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It is shown that there exist functions on the boundary of the unit disk whose graphs are complete pluripolar. Moreover, for any natural number k, such functions are dense in the space of functions on the boundary of the unit disk. We show that this result implies that the complete pluripolar closed curves are dense in the space of closed curves in ℂⁿ. We also show that on each closed subset of the complex plane there is a continuous function whose graph is complete pluripolar. ...
Huijun Fan, Tyler Jarvis, Yongbin Ruan (2011)
Annales de l’institut Fourier
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We give a review of our construction of a cohomological field theory for quasi-homogeneous singularities and the -spin theory of Jarvis-Kimura-Vaintrob. We further prove that for a singularity of type our construction of the stack of -curves is canonically isomorphic to the stack of -spin curves described by Abramovich and Jarvis. We further prove that our theory satisfies all the Jarvis-Kimura-Vaintrob axioms for an -spin virtual class. Therefore, the Faber-Shadrin-Zvonkine...
Vladimir Ya. Gutlyanskii, Olli Martio, Vladimir Ryazanov (2011)
Annales Universitatis Mariae Curie-Sklodowska, sectio A – Mathematica
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We give a quasiconformal version of the proof for the classical Lindelof theorem: Let map the unit disk conformally onto the inner domain of a Jordan curve : Then is smooth if and only if arg has a continuous extension to . Our proof does not use the Poisson integral representation of harmonic functions in the unit disk.
Laurent Bonavero, Cinzia Casagrande, Stéphane Druel (2007)
Journal of the European Mathematical Society
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Given a covering family of effective 1-cycles on a complex projective variety , we find conditions allowing one to construct a geometric quotient , with regular on the whole of , such that every fiber of is an equivalence class for the equivalence relation naturally defined by . Among other results, we show that on a normal and -factorial projective variety with canonical singularities and , every covering and quasi-unsplit family of rational curves generates a geometric...