# Central invariants revisited

Abstract : We use refined spectral sequence arguments to calculate known and previously unknown bi-Hamiltonian cohomology groups, which govern the deformation theory of semi-simple bi-Hamiltonian pencils of hydrodynamic type with one independent and $N$ dependent variables. In particular, we rederive the result of Dubrovin-Liu-Zhang that these deformations are parametrized by the so-called central invariants, which are $N$ smooth functions of one variable.
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Journal articles

https://hal.archives-ouvertes.fr/hal-01960202
Contributor : Imb - Université de Bourgogne <>
Submitted on : Wednesday, December 19, 2018 - 11:40:50 AM
Last modification on : Thursday, December 20, 2018 - 1:06:29 AM

### Citation

Guido Carlet, Reinier Kramer, Sergey Shadrin. Central invariants revisited. Journal de l'École polytechnique — Mathématiques, École polytechnique, 2018, 5, pp.149-175. ⟨10.5802/jep.66⟩. ⟨hal-01960202⟩

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