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[Merged by Bors] - feat(Probability/Kernel): disintegration of finite kernels #10603
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Mathlib/Probability/Kernel/Disintegration/MeasurableStieltjes.lean
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The refactor is done and this is ready for review. The PR is big, but if I dismantle the old disintegration file I have to have all the replacements in the PR (which means I can't PR the files about integrals and uniqueness later). |
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This looks great, thanks! Sorry for the delay to review the PR (it means there is another merge conflict that you have to solve...)
bors d+
This theorem in the case of finite kernels is weaker than `eq_condKernel_of_measure_eq_compProd` | ||
which asserts that the kernels are equal almost everywhere and not just on a given measurable | ||
set. -/ | ||
theorem eq_condKernel_of_measure_eq_compProd' (κ : kernel α Ω) [IsSFiniteKernel κ] |
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I think I am unhappy with the assumptions in this theorem and in the next ones: if ρ = ρ.fst ⊗ₘ κ
and ρ
is a finite measure, then κ a
should have finite mass almost everywhere wrt ρ.fst
, and I feel that this should be sufficient to carry out the arguments in the lemma without the assumptions of s-finiteness or of finiteness. However, the lemmas were already there (at least in the measure version) and you just copied them, so this shouldn't hold the PR back. I'll investigate that once this one is merged, if you agree.
✌️ RemyDegenne can now approve this pull request. To approve and merge a pull request, simply reply with |
Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr>
Thanks for all the reviews and for your help on the disintegration PRs. No worries about the review time: I don't expect a quick review for a 1000 lines PR :) bors r+ |
Let `κ : kernel α (β × Ω)` be a finite kernel, where `Ω` is a standard Borel space. Then if `α` is countable or `β` has a countably generated σ-algebra (for example if it is standard Borel), then there exists a `kernel (α × β) Ω` called conditional kernel and denoted by `condKernel κ` such that `κ = fst κ ⊗ₖ condKernel κ`. Properties of integrals involving `condKernel` are collated in the file `Integral.lean`. The conditional kernel is unique (almost everywhere w.r.t. `fst κ`): this is proved in the file `Unique.lean`. Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr> Co-authored-by: Rémy Degenne <remydegenne@gmail.com>
Pull request successfully merged into master. Build succeeded: |
Let `κ : kernel α (β × Ω)` be a finite kernel, where `Ω` is a standard Borel space. Then if `α` is countable or `β` has a countably generated σ-algebra (for example if it is standard Borel), then there exists a `kernel (α × β) Ω` called conditional kernel and denoted by `condKernel κ` such that `κ = fst κ ⊗ₖ condKernel κ`. Properties of integrals involving `condKernel` are collated in the file `Integral.lean`. The conditional kernel is unique (almost everywhere w.r.t. `fst κ`): this is proved in the file `Unique.lean`. Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr> Co-authored-by: Rémy Degenne <remydegenne@gmail.com>
Let `κ : kernel α (β × Ω)` be a finite kernel, where `Ω` is a standard Borel space. Then if `α` is countable or `β` has a countably generated σ-algebra (for example if it is standard Borel), then there exists a `kernel (α × β) Ω` called conditional kernel and denoted by `condKernel κ` such that `κ = fst κ ⊗ₖ condKernel κ`. Properties of integrals involving `condKernel` are collated in the file `Integral.lean`. The conditional kernel is unique (almost everywhere w.r.t. `fst κ`): this is proved in the file `Unique.lean`. Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr> Co-authored-by: Rémy Degenne <remydegenne@gmail.com>
Let `κ : kernel α (β × Ω)` be a finite kernel, where `Ω` is a standard Borel space. Then if `α` is countable or `β` has a countably generated σ-algebra (for example if it is standard Borel), then there exists a `kernel (α × β) Ω` called conditional kernel and denoted by `condKernel κ` such that `κ = fst κ ⊗ₖ condKernel κ`. Properties of integrals involving `condKernel` are collated in the file `Integral.lean`. The conditional kernel is unique (almost everywhere w.r.t. `fst κ`): this is proved in the file `Unique.lean`. Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr> Co-authored-by: Rémy Degenne <remydegenne@gmail.com>
Let `κ : kernel α (β × Ω)` be a finite kernel, where `Ω` is a standard Borel space. Then if `α` is countable or `β` has a countably generated σ-algebra (for example if it is standard Borel), then there exists a `kernel (α × β) Ω` called conditional kernel and denoted by `condKernel κ` such that `κ = fst κ ⊗ₖ condKernel κ`. Properties of integrals involving `condKernel` are collated in the file `Integral.lean`. The conditional kernel is unique (almost everywhere w.r.t. `fst κ`): this is proved in the file `Unique.lean`. Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr> Co-authored-by: Rémy Degenne <remydegenne@gmail.com>
Let
κ : kernel α (β × Ω)
be a finite kernel, whereΩ
is a standard Borel space. Then ifα
is countable orβ
has a countably generated σ-algebra (for example if it is standard Borel), then there exists akernel (α × β) Ω
called conditional kernel and denoted bycondKernel κ
such thatκ = fst κ ⊗ₖ condKernel κ
.Properties of integrals involving
condKernel
are collated in the fileIntegral.lean
.The conditional kernel is unique (almost everywhere w.r.t.
fst κ
): this is proved in the fileUnique.lean
.