Osaka Journal of Mathematics

On the Benson-Ratcliff invariant of coadjoint orbits on nilpotent Lie groups

Ali Baklouti and Khaled Tounsi

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We provide in this paper a counterexample to the Benson-Ratcliff conjecture about a cohomology class invariant on coadjoint orbits on nilpotent Lie groups. We prove that this invariant never vanishes on generic coadjoint orbits for some restrictive classes. As such, it does separate up to invariant factor, unitary representations associated to generic orbits in some cases.

Article information

Osaka J. Math., Volume 44, Number 2 (2007), 399-414.

First available in Project Euclid: 5 July 2007

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Mathematical Reviews number (MathSciNet)

Zentralblatt MATH identifier

Primary: 22E27: Representations of nilpotent and solvable Lie groups (special orbital integrals, non-type I representations, etc.) 22D10: Unitary representations of locally compact groups


Baklouti, Ali; Tounsi, Khaled. On the Benson-Ratcliff invariant of coadjoint orbits on nilpotent Lie groups. Osaka J. Math. 44 (2007), no. 2, 399--414.

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