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Philipp Hartwig
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Please assume that $G/S$ is an abelian scheme if it helps.

Let $G/S$ be a commutative group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

By ulrich's answer below the statement is true whenever 2 is invertible on $G$. But what if $G$ has points of characteristic 2?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

Let $G/S$ be a commutative group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

By ulrich's answer below the statement is true whenever 2 is invertible on $G$. But what if $G$ has points of characteristic 2?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

Please assume that $G/S$ is an abelian scheme if it helps.

Let $G/S$ be a commutative group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

By ulrich's answer below the statement is true whenever 2 is invertible on $G$. But what if $G$ has points of characteristic 2?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

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Philipp Hartwig
  • 1.6k
  • 1
  • 18
  • 17

Let $G/S$ be a commutative group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

By ulrich's answer below the statement is true whenever 2 is invertible on $G$. But what if $G$ has points of characteristic 2?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

Let $G/S$ be a commutative group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

Let $G/S$ be a commutative group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

By ulrich's answer below the statement is true whenever 2 is invertible on $G$. But what if $G$ has points of characteristic 2?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

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Philipp Hartwig
  • 1.6k
  • 1
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  • 17

Invariant differential forms on commutative group schemes are closed!?

Let $G/S$ be a commutative group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

Invariant differential forms on group schemes are closed!?

Let $G/S$ be a group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

Invariant differential forms on commutative group schemes are closed!?

Let $G/S$ be a commutative group scheme and let $(\Omega^\bullet_{G/S},d)$ be the algebraic de Rham complex. Let $\omega\in \Omega^r_{G/S}(G)$ be an invariant r-form. Is it true in this generality that $d\omega=0$? Is there a reference for such a fact?

I'm trying to understand the proof of the degeneracy of the Hodge-de Rham spectral sequence for abelian schemes from Berthelot-Breen-Messing, Théorie de Dieudonné cristalline II, specifically Lemma 2.5.3. In its proof they say "Comme les différentielles invariantes sont fermées[...]".

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Philipp Hartwig
  • 1.6k
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  • 17
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