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[Merged by Bors] - feat(probability_theory/independence): prove equivalences for indep_set #6242
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I think a more principled approach to @[simp] lemma union_univ {s : set α} : s ∪ univ = univ := sorry
@[simp] lemma univ_union {s : set α} : univ ∪ s = univ := sorry
lemma generate_from_of_finite
(S : set (set α)) (hcompl : ∀ s ∈ S, sᶜ ∈ S) (hempty : ∅ ∈ S) (hfin : finite S)
(hun : ∀ s ∈ S, ∀ t ∈ S, s ∪ t ∈ S) :
generate_measurable S = S :=
let m : measurable_space α :=
{ measurable_set' := S,
measurable_set_empty := hempty,
measurable_set_compl := hcompl,
measurable_set_Union := sorry } in
le_antisymm (generate_from_le (λ t ht, ht) : generate_from S ≤ m)
(λ t ht, measurable_set_generate_from ht)
lemma generate_from_set (s : set α) :
generate_measurable ({∅, set.univ, s, sᶜ} : set (set α)) = ({∅, set.univ, s, sᶜ} : set (set α)) :=
generate_from_of_finite _ (by simp) (by simp) (by simp) (by simp) Note that |
Thanks for the better approach. |
Co-authored-by: Rémy Degenne <remydegenne@gmail.com>
Co-authored-by: Rémy Degenne <remydegenne@gmail.com>
…mathlib into mzinkevi_pi_system
I changed the proof to use a much simpler approach, using the fact that All statements about |
🎉 Great news! Looks like all the dependencies have been resolved: 💡 To add or remove a dependency please update this issue/PR description. Brought to you by Dependent Issues (:robot: ). Happy coding! |
bors r+ |
…et (#6242) Prove the following equivalences on `indep_set`, for measurable sets `s,t` and a probability measure `µ` : * `indep_set s t μ ↔ μ (s ∩ t) = μ s * μ t`, * `indep_set s t μ ↔ indep_sets {s} {t} μ`. In `indep_sets.indep_set_of_mem`, we use those equivalences to obtain `indep_set s t µ` from `indep_sets S T µ` and `s ∈ S`, `t ∈ T`. Co-authored-by: mzinkevi <martinz@google.com> Co-authored-by: mzinkevi <41597957+mzinkevi@users.noreply.github.com>
Build failed (retrying...): |
…et (#6242) Prove the following equivalences on `indep_set`, for measurable sets `s,t` and a probability measure `µ` : * `indep_set s t μ ↔ μ (s ∩ t) = μ s * μ t`, * `indep_set s t μ ↔ indep_sets {s} {t} μ`. In `indep_sets.indep_set_of_mem`, we use those equivalences to obtain `indep_set s t µ` from `indep_sets S T µ` and `s ∈ S`, `t ∈ T`. Co-authored-by: mzinkevi <martinz@google.com> Co-authored-by: mzinkevi <41597957+mzinkevi@users.noreply.github.com>
Pull request successfully merged into master. Build succeeded: |
…et (#6242) Prove the following equivalences on `indep_set`, for measurable sets `s,t` and a probability measure `µ` : * `indep_set s t μ ↔ μ (s ∩ t) = μ s * μ t`, * `indep_set s t μ ↔ indep_sets {s} {t} μ`. In `indep_sets.indep_set_of_mem`, we use those equivalences to obtain `indep_set s t µ` from `indep_sets S T µ` and `s ∈ S`, `t ∈ T`. Co-authored-by: mzinkevi <martinz@google.com> Co-authored-by: mzinkevi <41597957+mzinkevi@users.noreply.github.com>
Prove the following equivalences on
indep_set
, for measurable setss,t
and a probability measureµ
:indep_set s t μ ↔ μ (s ∩ t) = μ s * μ t
,indep_set s t μ ↔ indep_sets {s} {t} μ
.In
indep_sets.indep_set_of_mem
, we use those equivalences to obtainindep_set s t µ
fromindep_sets S T µ
ands ∈ S
,t ∈ T
.