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Pablo
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Let $G$ be a finitely generated profinite group, $p$ a prime number. Put $$ V = \prod_{i \in I} \mathbb{Z}_p$$ a (profinite) group equipped with the product topology (for convenience, $I$ may be assumed to be countable). Suppose that $G$ acts by continuous automorphisms on $V$ (this means that $G$ acts continuously on $V$ respecting its group law, i.e $V$ is a profinte $G$-module. I am mainly interested in actions coming from extensions).

  1. Must $V$ contain a closed, nontrivial, topologically finitely generated subgroup invariant under the action of $G$?

  2. Must $V$ contain a nontrivial pair of trivially intersecting $G$-submodules?

  3. Is there a way to decompose $V$ into a nontrivial direct product of $G$-submodules?

I am equally interested in the case of $\mathbb{F}_p$ (the field of cardinality $p$) in place of $\mathbb{Z}_p$ (the $p$-adic integers).

Let $G$ be a finitely generated profinite group, $p$ a prime number. Put $$ V = \prod_{i \in I} \mathbb{Z}_p$$ a (profinite) group equipped with the product topology (for convenience, $I$ may be assumed to be countable). Suppose that $G$ acts by continuous automorphisms on $V$ (this means that $G$ acts continuously on $V$ respecting its group law, i.e $V$ is a profinte $G$-module. I am mainly interested in actions coming from extensions).

  1. Must $V$ contain a closed, nontrivial, topologically finitely generated subgroup invariant under the action of $G$?

  2. Must $V$ contain a nontrivial pair of trivially intersecting $G$-submodules?

  3. Is there a way to decompose $V$ into a direct product of $G$-submodules?

I am equally interested in the case of $\mathbb{F}_p$ in place of $\mathbb{Z}_p$.

Let $G$ be a finitely generated profinite group, $p$ a prime number. Put $$ V = \prod_{i \in I} \mathbb{Z}_p$$ a (profinite) group equipped with the product topology (for convenience, $I$ may be assumed to be countable). Suppose that $G$ acts by continuous automorphisms on $V$ (this means that $G$ acts continuously on $V$ respecting its group law, i.e $V$ is a profinte $G$-module. I am mainly interested in actions coming from extensions).

  1. Must $V$ contain a closed, nontrivial, topologically finitely generated subgroup invariant under the action of $G$?

  2. Must $V$ contain a nontrivial pair of trivially intersecting $G$-submodules?

  3. Is there a way to decompose $V$ into a nontrivial direct product of $G$-submodules?

I am equally interested in the case of $\mathbb{F}_p$ (the field of cardinality $p$) in place of $\mathbb{Z}_p$ (the $p$-adic integers).

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Pablo
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Let $G$ be a finitely generated profinite group, $p$ a prime number. Put $$ V = \prod_{i \in I} \mathbb{Z}_p$$ a (profinite) group equipped with the product topology (for convenience, $I$ may be assumed to be countable). Suppose that $G$ acts by continuous automorphisms on $V$ (this means that $G$ acts continuously on $V$ respecting its group law, i.e $V$ is a profinte $G$-module. I am mainly interested in actions coming from extensions).

  1. Must $V$ contain a closed, nontrivial, topologically finitely generated subgroup invariant under the action of $G$-submodule?

  2. Must $V$ contain a nontrivial pair of trivially intersecting $G$-submodules?

  3. Is there a way to decompose $V$ into a direct product of $G$-submodules?

I am equally interested in the case of $\mathbb{F}_p$ in place of $\mathbb{Z}_p$.

Let $G$ be a finitely generated profinite group, $p$ a prime number. Put $$ V = \prod_{i \in I} \mathbb{Z}_p$$ a (profinite) group equipped with the product topology (for convenience, $I$ may be assumed to be countable). Suppose that $G$ acts by continuous automorphisms on $V$ (this means that $G$ acts continuously on $V$ respecting its group law, i.e $V$ is a profinte $G$-module. I am mainly interested in actions coming from extensions).

  1. Must $V$ contain a topologically finitely generated $G$-submodule?

  2. Must $V$ contain a pair of trivially intersecting $G$-submodules?

  3. Is there a way to decompose $V$ into a direct product of $G$-submodules?

I am equally interested in the case of $\mathbb{F}_p$ in place of $\mathbb{Z}_p$.

Let $G$ be a finitely generated profinite group, $p$ a prime number. Put $$ V = \prod_{i \in I} \mathbb{Z}_p$$ a (profinite) group equipped with the product topology (for convenience, $I$ may be assumed to be countable). Suppose that $G$ acts by continuous automorphisms on $V$ (this means that $G$ acts continuously on $V$ respecting its group law, i.e $V$ is a profinte $G$-module. I am mainly interested in actions coming from extensions).

  1. Must $V$ contain a closed, nontrivial, topologically finitely generated subgroup invariant under the action of $G$?

  2. Must $V$ contain a nontrivial pair of trivially intersecting $G$-submodules?

  3. Is there a way to decompose $V$ into a direct product of $G$-submodules?

I am equally interested in the case of $\mathbb{F}_p$ in place of $\mathbb{Z}_p$.

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Pablo
  • 11.3k
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  • 68

Action of a profinite group

Let $G$ be a finitely generated profinite group, $p$ a prime number. Put $$ V = \prod_{i \in I} \mathbb{Z}_p$$ a (profinite) group equipped with the product topology (for convenience, $I$ may be assumed to be countable). Suppose that $G$ acts by continuous automorphisms on $V$ (this means that $G$ acts continuously on $V$ respecting its group law, i.e $V$ is a profinte $G$-module. I am mainly interested in actions coming from extensions).

  1. Must $V$ contain a topologically finitely generated $G$-submodule?

  2. Must $V$ contain a pair of trivially intersecting $G$-submodules?

  3. Is there a way to decompose $V$ into a direct product of $G$-submodules?

I am equally interested in the case of $\mathbb{F}_p$ in place of $\mathbb{Z}_p$.