Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The existence of closed 3-forms of $\tilde G_2$-type on 7-manifolds   In this note we construct a first example of a closed 3-form of $\tilde
G_2$-type on $S^3\times S^4$. We prove that $S^3\times S^4$ does not admit a
homogeneous
  3-form of $\tilde G_2$-type. Thus our example is a first example of a closed
3-form of $\tilde G_2$-type on a compact 7-manifold which is not stably
homogeneous.

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The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: cond-mat
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: cs
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th