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[Merged by Bors] - feat(probability/martingale): the discrete stochastic integral of a submartingale is a submartingale #14909

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@JasonKYi JasonKYi commented Jun 23, 2022

@JasonKYi JasonKYi added the WIP Work in progress label Jun 23, 2022
@JasonKYi JasonKYi added this to In progress in Martingale theory Jun 23, 2022
@mathlib-dependent-issues-bot mathlib-dependent-issues-bot added the blocked-by-other-PR This PR depends on another PR which is still in the queue. A bot manages this label via PR comment. label Jun 23, 2022
@mathlib-dependent-issues-bot mathlib-dependent-issues-bot removed the blocked-by-other-PR This PR depends on another PR which is still in the queue. A bot manages this label via PR comment. label Jun 24, 2022
@mathlib-dependent-issues-bot mathlib-dependent-issues-bot added blocked-by-other-PR This PR depends on another PR which is still in the queue. A bot manages this label via PR comment. and removed blocked-by-other-PR This PR depends on another PR which is still in the queue. A bot manages this label via PR comment. labels Jun 25, 2022
bors bot pushed a commit that referenced this pull request Jul 26, 2022
…rty of the conditional expectation (#15274)

We prove this result:
```lean
lemma condexp_strongly_measurable_mul {f g : α → ℝ} (hf : strongly_measurable[m] f)
  (hfg : integrable (f * g) μ) (hg : integrable g μ) :
  μ[f * g | m] =ᵐ[μ] f * μ[g | m] :=
```
This could be extended beyond multiplication, to any bounded bilinear map, but we leave this to a future PR. For now we only prove the real multiplication case, which is needed for #14909 and #14933.
@mathlib-dependent-issues-bot mathlib-dependent-issues-bot removed the blocked-by-other-PR This PR depends on another PR which is still in the queue. A bot manages this label via PR comment. label Jul 26, 2022
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Could you please merge master?

@RemyDegenne RemyDegenne added awaiting-author A reviewer has asked the author a question or requested changes and removed awaiting-review The author would like community review of the PR labels Jul 27, 2022
@JasonKYi JasonKYi added awaiting-review The author would like community review of the PR and removed awaiting-author A reviewer has asked the author a question or requested changes labels Jul 27, 2022
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Thanks!
bors d+

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bors bot commented Jul 27, 2022

✌️ JasonKYi can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

@leanprover-community-bot-assistant leanprover-community-bot-assistant added delegated The PR author may merge after reviewing final suggestions. and removed awaiting-review The author would like community review of the PR labels Jul 27, 2022
Co-authored-by: Rémy Degenne <remydegenne@gmail.com>
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Thanks for the reviews!
bors r+

bors bot pushed a commit that referenced this pull request Jul 27, 2022
…ubmartingale is a submartingale (#14909)

This PR proves that the discrete stochastic integral of a predictable process with a submartingale is a submartingale.



Co-authored-by: RemyDegenne <Remydegenne@gmail.com>
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bors bot commented Jul 27, 2022

Pull request successfully merged into master.

Build succeeded:

@bors bors bot changed the title feat(probability/martingale): the discrete stochastic integral of a submartingale is a submartingale [Merged by Bors] - feat(probability/martingale): the discrete stochastic integral of a submartingale is a submartingale Jul 27, 2022
@bors bors bot closed this Jul 27, 2022
Martingale theory automation moved this from Under review to Done! 🎉 Jul 27, 2022
@bors bors bot deleted the JasonKYi/disc_stoch_int branch July 27, 2022 21:21
bottine pushed a commit to bottine/mathlib that referenced this pull request Jul 30, 2022
…rty of the conditional expectation (leanprover-community#15274)

We prove this result:
```lean
lemma condexp_strongly_measurable_mul {f g : α → ℝ} (hf : strongly_measurable[m] f)
  (hfg : integrable (f * g) μ) (hg : integrable g μ) :
  μ[f * g | m] =ᵐ[μ] f * μ[g | m] :=
```
This could be extended beyond multiplication, to any bounded bilinear map, but we leave this to a future PR. For now we only prove the real multiplication case, which is needed for leanprover-community#14909 and leanprover-community#14933.
bottine pushed a commit to bottine/mathlib that referenced this pull request Jul 30, 2022
…ubmartingale is a submartingale (leanprover-community#14909)

This PR proves that the discrete stochastic integral of a predictable process with a submartingale is a submartingale.



Co-authored-by: RemyDegenne <Remydegenne@gmail.com>
robertylewis pushed a commit that referenced this pull request Aug 2, 2022
…rty of the conditional expectation (#15274)

We prove this result:
```lean
lemma condexp_strongly_measurable_mul {f g : α → ℝ} (hf : strongly_measurable[m] f)
  (hfg : integrable (f * g) μ) (hg : integrable g μ) :
  μ[f * g | m] =ᵐ[μ] f * μ[g | m] :=
```
This could be extended beyond multiplication, to any bounded bilinear map, but we leave this to a future PR. For now we only prove the real multiplication case, which is needed for #14909 and #14933.
robertylewis pushed a commit that referenced this pull request Aug 2, 2022
…ubmartingale is a submartingale (#14909)

This PR proves that the discrete stochastic integral of a predictable process with a submartingale is a submartingale.



Co-authored-by: RemyDegenne <Remydegenne@gmail.com>
khwilson pushed a commit that referenced this pull request Aug 2, 2022
…rty of the conditional expectation (#15274)

We prove this result:
```lean
lemma condexp_strongly_measurable_mul {f g : α → ℝ} (hf : strongly_measurable[m] f)
  (hfg : integrable (f * g) μ) (hg : integrable g μ) :
  μ[f * g | m] =ᵐ[μ] f * μ[g | m] :=
```
This could be extended beyond multiplication, to any bounded bilinear map, but we leave this to a future PR. For now we only prove the real multiplication case, which is needed for #14909 and #14933.
khwilson pushed a commit that referenced this pull request Aug 2, 2022
…ubmartingale is a submartingale (#14909)

This PR proves that the discrete stochastic integral of a predictable process with a submartingale is a submartingale.



Co-authored-by: RemyDegenne <Remydegenne@gmail.com>
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