Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Central invariants revisited   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.

17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
3
The categories of this paper are: physics