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Full-Text Articles in Physical Sciences and Mathematics

Bohr Density Of Simple Linear Group Orbits, Roger Howe, François Ziegler May 2015

Bohr Density Of Simple Linear Group Orbits, Roger Howe, François Ziegler

François Ziegler

We show that any non-zero orbit under a non-compact, simple, irreducible linear group is dense in the Bohr compactification of the ambient space.


Local Well-Posedness Of Periodic Fifth Order Kdv-Type Equations, Yi Hu, Xiaochun Li Apr 2015

Local Well-Posedness Of Periodic Fifth Order Kdv-Type Equations, Yi Hu, Xiaochun Li

Yi Hu

In this paper, the local well-posedness of periodic fifth order dispersive equation with nonlinear term P1(u)∂xu + P2(u)∂xu∂xu. Here P1(u) and P2(u) are polynomials of u. We also get some new Strichartz estimates.


Primary Spaces, Mackey’S Obstruction, And The Generalized Barycentric Decomposition, Patrick Iglesias-Zemmour, François Ziegler Jan 2015

Primary Spaces, Mackey’S Obstruction, And The Generalized Barycentric Decomposition, Patrick Iglesias-Zemmour, François Ziegler

François Ziegler

We call a hamiltonian N-space primary if its moment map is onto a single coadjoint orbit. The question has long been open whether such spaces always split as (homogeneous) × (trivial), as an analogy with representation theory might suggest. For instance, Souriau’s barycentric decomposition theorem asserts just this when N is a Heisenberg group. For general N, we give explicit examples which do not split, and show instead that primary spaces are always flat bundles over the coadjoint orbit. This provides the missing piece for a full “Mackey theory” of hamiltonian G-spaces, where G is an overgroup in which N …