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Type | Label | Description |
---|---|---|
Statement | ||
Theorem | measun 29601 | The measure the union of two disjoint sets is the sum of their measures. (Contributed by Thierry Arnoux, 10-Mar-2017.) |
⊢ ((𝑀 ∈ (measures‘𝑆) ∧ (𝐴 ∈ 𝑆 ∧ 𝐵 ∈ 𝑆) ∧ (𝐴 ∩ 𝐵) = ∅) → (𝑀‘(𝐴 ∪ 𝐵)) = ((𝑀‘𝐴) +𝑒 (𝑀‘𝐵))) | ||
Theorem | measvunilem 29602* | Lemma for measvuni 29604. (Contributed by Thierry Arnoux, 7-Feb-2017.) (Revised by Thierry Arnoux, 19-Feb-2017.) (Revised by Thierry Arnoux, 6-Mar-2017.) |
⊢ Ⅎ𝑥𝐴 ⇒ ⊢ ((𝑀 ∈ (measures‘𝑆) ∧ ∀𝑥 ∈ 𝐴 𝐵 ∈ (𝑆 ∖ {∅}) ∧ (𝐴 ≼ ω ∧ Disj 𝑥 ∈ 𝐴 𝐵)) → (𝑀‘∪ 𝑥 ∈ 𝐴 𝐵) = Σ*𝑥 ∈ 𝐴(𝑀‘𝐵)) | ||
Theorem | measvunilem0 29603* | Lemma for measvuni 29604. (Contributed by Thierry Arnoux, 6-Mar-2017.) |
⊢ Ⅎ𝑥𝐴 ⇒ ⊢ ((𝑀 ∈ (measures‘𝑆) ∧ ∀𝑥 ∈ 𝐴 𝐵 ∈ {∅} ∧ (𝐴 ≼ ω ∧ Disj 𝑥 ∈ 𝐴 𝐵)) → (𝑀‘∪ 𝑥 ∈ 𝐴 𝐵) = Σ*𝑥 ∈ 𝐴(𝑀‘𝐵)) | ||
Theorem | measvuni 29604* | The measure of a countable disjoint union is the sum of the measures. This theorem uses a collection rather than a set of subsets of 𝑆. (Contributed by Thierry Arnoux, 7-Mar-2017.) |
⊢ ((𝑀 ∈ (measures‘𝑆) ∧ ∀𝑥 ∈ 𝐴 𝐵 ∈ 𝑆 ∧ (𝐴 ≼ ω ∧ Disj 𝑥 ∈ 𝐴 𝐵)) → (𝑀‘∪ 𝑥 ∈ 𝐴 𝐵) = Σ*𝑥 ∈ 𝐴(𝑀‘𝐵)) | ||
Theorem | measssd 29605 | A measure is monotone with respect to set inclusion. (Contributed by Thierry Arnoux, 28-Dec-2016.) |
⊢ (𝜑 → 𝑀 ∈ (measures‘𝑆)) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → 𝐴 ⊆ 𝐵) ⇒ ⊢ (𝜑 → (𝑀‘𝐴) ≤ (𝑀‘𝐵)) | ||
Theorem | measunl 29606 | A measure is sub-additive with respect to union. (Contributed by Thierry Arnoux, 20-Oct-2017.) |
⊢ (𝜑 → 𝑀 ∈ (measures‘𝑆)) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ (𝜑 → 𝐵 ∈ 𝑆) ⇒ ⊢ (𝜑 → (𝑀‘(𝐴 ∪ 𝐵)) ≤ ((𝑀‘𝐴) +𝑒 (𝑀‘𝐵))) | ||
Theorem | measiuns 29607* | The measure of the union of a collection of sets, expressed as the sum of a disjoint set. This is used as a lemma for both measiun 29608 and meascnbl 29609. (Contributed by Thierry Arnoux, 22-Jan-2017.) (Proof shortened by Thierry Arnoux, 7-Feb-2017.) |
⊢ Ⅎ𝑛𝐵 & ⊢ (𝑛 = 𝑘 → 𝐴 = 𝐵) & ⊢ (𝜑 → (𝑁 = ℕ ∨ 𝑁 = (1..^𝐼))) & ⊢ (𝜑 → 𝑀 ∈ (measures‘𝑆)) & ⊢ ((𝜑 ∧ 𝑛 ∈ 𝑁) → 𝐴 ∈ 𝑆) ⇒ ⊢ (𝜑 → (𝑀‘∪ 𝑛 ∈ 𝑁 𝐴) = Σ*𝑛 ∈ 𝑁(𝑀‘(𝐴 ∖ ∪ 𝑘 ∈ (1..^𝑛)𝐵))) | ||
Theorem | measiun 29608* | A measure is sub-additive. (Contributed by Thierry Arnoux, 30-Dec-2016.) (Proof shortened by Thierry Arnoux, 7-Feb-2017.) |
⊢ (𝜑 → 𝑀 ∈ (measures‘𝑆)) & ⊢ (𝜑 → 𝐴 ∈ 𝑆) & ⊢ ((𝜑 ∧ 𝑛 ∈ ℕ) → 𝐵 ∈ 𝑆) & ⊢ (𝜑 → 𝐴 ⊆ ∪ 𝑛 ∈ ℕ 𝐵) ⇒ ⊢ (𝜑 → (𝑀‘𝐴) ≤ Σ*𝑛 ∈ ℕ(𝑀‘𝐵)) | ||
Theorem | meascnbl 29609* | A measure is continuous from below. Cf. volsup 23131. (Contributed by Thierry Arnoux, 18-Jan-2017.) (Revised by Thierry Arnoux, 11-Jul-2017.) |
⊢ 𝐽 = (TopOpen‘(ℝ*𝑠 ↾s (0[,]+∞))) & ⊢ (𝜑 → 𝑀 ∈ (measures‘𝑆)) & ⊢ (𝜑 → 𝐹:ℕ⟶𝑆) & ⊢ ((𝜑 ∧ 𝑛 ∈ ℕ) → (𝐹‘𝑛) ⊆ (𝐹‘(𝑛 + 1))) ⇒ ⊢ (𝜑 → (𝑀 ∘ 𝐹)(⇝𝑡‘𝐽)(𝑀‘∪ ran 𝐹)) | ||
Theorem | measinblem 29610* | Lemma for measinb 29611. (Contributed by Thierry Arnoux, 2-Jun-2017.) |
⊢ ((((𝑀 ∈ (measures‘𝑆) ∧ 𝐴 ∈ 𝑆) ∧ 𝐵 ∈ 𝒫 𝑆) ∧ (𝐵 ≼ ω ∧ Disj 𝑥 ∈ 𝐵 𝑥)) → (𝑀‘(∪ 𝐵 ∩ 𝐴)) = Σ*𝑥 ∈ 𝐵(𝑀‘(𝑥 ∩ 𝐴))) | ||
Theorem | measinb 29611* | Building a measure restricted to the intersection with a given set. (Contributed by Thierry Arnoux, 25-Dec-2016.) |
⊢ ((𝑀 ∈ (measures‘𝑆) ∧ 𝐴 ∈ 𝑆) → (𝑥 ∈ 𝑆 ↦ (𝑀‘(𝑥 ∩ 𝐴))) ∈ (measures‘𝑆)) | ||
Theorem | measres 29612 | Building a measure restricted to a smaller sigma-algebra. (Contributed by Thierry Arnoux, 25-Dec-2016.) |
⊢ ((𝑀 ∈ (measures‘𝑆) ∧ 𝑇 ∈ ∪ ran sigAlgebra ∧ 𝑇 ⊆ 𝑆) → (𝑀 ↾ 𝑇) ∈ (measures‘𝑇)) | ||
Theorem | measinb2 29613* | Building a measure restricted to the intersection with a given set. (Contributed by Thierry Arnoux, 25-Dec-2016.) |
⊢ ((𝑀 ∈ (measures‘𝑆) ∧ 𝐴 ∈ 𝑆) → (𝑥 ∈ (𝑆 ∩ 𝒫 𝐴) ↦ (𝑀‘(𝑥 ∩ 𝐴))) ∈ (measures‘(𝑆 ∩ 𝒫 𝐴))) | ||
Theorem | measdivcstOLD 29614* | Division of a measure by a positive constant is a measure. (Contributed by Thierry Arnoux, 25-Dec-2016.) (New usage is discouraged.) (Proof modification is discouraged.) |
⊢ ((𝑀 ∈ (measures‘𝑆) ∧ 𝐴 ∈ ℝ+) → (𝑥 ∈ 𝑆 ↦ ((𝑀‘𝑥) /𝑒 𝐴)) ∈ (measures‘𝑆)) | ||
Theorem | measdivcst 29615 | Division of a measure by a positive constant is a measure. (Contributed by Thierry Arnoux, 25-Dec-2016.) (Revised by Thierry Arnoux, 30-Jan-2017.) |
⊢ ((𝑀 ∈ (measures‘𝑆) ∧ 𝐴 ∈ ℝ+) → (𝑀∘𝑓/𝑐 /𝑒 𝐴) ∈ (measures‘𝑆)) | ||
Theorem | cntmeas 29616 | The Counting measure is a measure on any sigma-algebra. (Contributed by Thierry Arnoux, 25-Dec-2016.) |
⊢ (𝑆 ∈ ∪ ran sigAlgebra → (# ↾ 𝑆) ∈ (measures‘𝑆)) | ||
Theorem | pwcntmeas 29617 | The counting measure is a measure on any power set. (Contributed by Thierry Arnoux, 24-Jan-2017.) |
⊢ (𝑂 ∈ 𝑉 → (# ↾ 𝒫 𝑂) ∈ (measures‘𝒫 𝑂)) | ||
Theorem | cntnevol 29618 | Counting and Lebesgue measures are different. (Contributed by Thierry Arnoux, 27-Jan-2017.) |
⊢ (# ↾ 𝒫 𝑂) ≠ vol | ||
Theorem | voliune 29619 | The Lebesgue measure function is countably additive. This formulation on the extended reals, allows for +∞ for the measure of any set in the sum. Cf. ovoliun 23080 and voliun 23129. (Contributed by Thierry Arnoux, 16-Oct-2017.) |
⊢ ((∀𝑛 ∈ ℕ 𝐴 ∈ dom vol ∧ Disj 𝑛 ∈ ℕ 𝐴) → (vol‘∪ 𝑛 ∈ ℕ 𝐴) = Σ*𝑛 ∈ ℕ(vol‘𝐴)) | ||
Theorem | volfiniune 29620* | The Lebesgue measure function is countably additive. This theorem is to volfiniun 23122 what voliune 29619 is to voliun 23129. (Contributed by Thierry Arnoux, 16-Oct-2017.) |
⊢ ((𝐴 ∈ Fin ∧ ∀𝑛 ∈ 𝐴 𝐵 ∈ dom vol ∧ Disj 𝑛 ∈ 𝐴 𝐵) → (vol‘∪ 𝑛 ∈ 𝐴 𝐵) = Σ*𝑛 ∈ 𝐴(vol‘𝐵)) | ||
Theorem | volmeas 29621 | The Lebesgue measure is a measure. (Contributed by Thierry Arnoux, 16-Oct-2017.) |
⊢ vol ∈ (measures‘dom vol) | ||
Syntax | cdde 29622 | Extend class notation to include the Dirac delta measure. |
class δ | ||
Definition | df-dde 29623 | Define the Dirac delta measure. (Contributed by Thierry Arnoux, 14-Sep-2018.) |
⊢ δ = (𝑎 ∈ 𝒫 ℝ ↦ if(0 ∈ 𝑎, 1, 0)) | ||
Theorem | ddeval1 29624 | Value of the delta measure. (Contributed by Thierry Arnoux, 14-Sep-2018.) |
⊢ ((𝐴 ⊆ ℝ ∧ 0 ∈ 𝐴) → (δ‘𝐴) = 1) | ||
Theorem | ddeval0 29625 | Value of the delta measure. (Contributed by Thierry Arnoux, 14-Sep-2018.) |
⊢ ((𝐴 ⊆ ℝ ∧ ¬ 0 ∈ 𝐴) → (δ‘𝐴) = 0) | ||
Theorem | ddemeas 29626 | The Dirac delta measure is a measure. (Contributed by Thierry Arnoux, 14-Sep-2018.) |
⊢ δ ∈ (measures‘𝒫 ℝ) | ||
Syntax | cae 29627 | Extend class notation to include the 'almost everywhere' relation. |
class a.e. | ||
Syntax | cfae 29628 | Extend class notation to include the 'almost everywhere' builder. |
class ~ a.e. | ||
Definition | df-ae 29629* | Define 'almost everywhere' with regard to a measure 𝑀. A property holds almost everywhere if the measure of the set where it does not hold has measure zero. (Contributed by Thierry Arnoux, 20-Oct-2017.) |
⊢ a.e. = {〈𝑎, 𝑚〉 ∣ (𝑚‘(∪ dom 𝑚 ∖ 𝑎)) = 0} | ||
Theorem | relae 29630 | 'almost everywhere' is a relation. (Contributed by Thierry Arnoux, 20-Oct-2017.) |
⊢ Rel a.e. | ||
Theorem | brae 29631 | 'almost everywhere' relation for a measure and a measurable set 𝐴. (Contributed by Thierry Arnoux, 20-Oct-2017.) |
⊢ ((𝑀 ∈ ∪ ran measures ∧ 𝐴 ∈ dom 𝑀) → (𝐴a.e.𝑀 ↔ (𝑀‘(∪ dom 𝑀 ∖ 𝐴)) = 0)) | ||
Theorem | braew 29632* | 'almost everywhere' relation for a measure 𝑀 and a property 𝜑 (Contributed by Thierry Arnoux, 20-Oct-2017.) |
⊢ ∪ dom 𝑀 = 𝑂 ⇒ ⊢ (𝑀 ∈ ∪ ran measures → ({𝑥 ∈ 𝑂 ∣ 𝜑}a.e.𝑀 ↔ (𝑀‘{𝑥 ∈ 𝑂 ∣ ¬ 𝜑}) = 0)) | ||
Theorem | truae 29633* | A truth holds almost everywhere. (Contributed by Thierry Arnoux, 20-Oct-2017.) |
⊢ ∪ dom 𝑀 = 𝑂 & ⊢ (𝜑 → 𝑀 ∈ ∪ ran measures) & ⊢ (𝜑 → 𝜓) ⇒ ⊢ (𝜑 → {𝑥 ∈ 𝑂 ∣ 𝜓}a.e.𝑀) | ||
Theorem | aean 29634* | A conjunction holds almost everywhere if and only if both its terms do. (Contributed by Thierry Arnoux, 20-Oct-2017.) |
⊢ ∪ dom 𝑀 = 𝑂 ⇒ ⊢ ((𝑀 ∈ ∪ ran measures ∧ {𝑥 ∈ 𝑂 ∣ ¬ 𝜑} ∈ dom 𝑀 ∧ {𝑥 ∈ 𝑂 ∣ ¬ 𝜓} ∈ dom 𝑀) → ({𝑥 ∈ 𝑂 ∣ (𝜑 ∧ 𝜓)}a.e.𝑀 ↔ ({𝑥 ∈ 𝑂 ∣ 𝜑}a.e.𝑀 ∧ {𝑥 ∈ 𝑂 ∣ 𝜓}a.e.𝑀))) | ||
Definition | df-fae 29635* | Define a builder for an 'almost everywhere' relation between functions, from relations between function values. In this definition, the range of 𝑓 and 𝑔 is enforced in order to ensure the resulting relation is a set. (Contributed by Thierry Arnoux, 22-Oct-2017.) |
⊢ ~ a.e. = (𝑟 ∈ V, 𝑚 ∈ ∪ ran measures ↦ {〈𝑓, 𝑔〉 ∣ ((𝑓 ∈ (dom 𝑟 ↑𝑚 ∪ dom 𝑚) ∧ 𝑔 ∈ (dom 𝑟 ↑𝑚 ∪ dom 𝑚)) ∧ {𝑥 ∈ ∪ dom 𝑚 ∣ (𝑓‘𝑥)𝑟(𝑔‘𝑥)}a.e.𝑚)}) | ||
Theorem | faeval 29636* | Value of the 'almost everywhere' relation for a given relation and measure. (Contributed by Thierry Arnoux, 22-Oct-2017.) |
⊢ ((𝑅 ∈ V ∧ 𝑀 ∈ ∪ ran measures) → (𝑅~ a.e.𝑀) = {〈𝑓, 𝑔〉 ∣ ((𝑓 ∈ (dom 𝑅 ↑𝑚 ∪ dom 𝑀) ∧ 𝑔 ∈ (dom 𝑅 ↑𝑚 ∪ dom 𝑀)) ∧ {𝑥 ∈ ∪ dom 𝑀 ∣ (𝑓‘𝑥)𝑅(𝑔‘𝑥)}a.e.𝑀)}) | ||
Theorem | relfae 29637 | The 'almost everywhere' builder for functions produces relations. (Contributed by Thierry Arnoux, 22-Oct-2017.) |
⊢ ((𝑅 ∈ V ∧ 𝑀 ∈ ∪ ran measures) → Rel (𝑅~ a.e.𝑀)) | ||
Theorem | brfae 29638* | 'almost everywhere' relation for two functions 𝐹 and 𝐺 with regard to the measure 𝑀. (Contributed by Thierry Arnoux, 22-Oct-2017.) |
⊢ dom 𝑅 = 𝐷 & ⊢ (𝜑 → 𝑅 ∈ V) & ⊢ (𝜑 → 𝑀 ∈ ∪ ran measures) & ⊢ (𝜑 → 𝐹 ∈ (𝐷 ↑𝑚 ∪ dom 𝑀)) & ⊢ (𝜑 → 𝐺 ∈ (𝐷 ↑𝑚 ∪ dom 𝑀)) ⇒ ⊢ (𝜑 → (𝐹(𝑅~ a.e.𝑀)𝐺 ↔ {𝑥 ∈ ∪ dom 𝑀 ∣ (𝐹‘𝑥)𝑅(𝐺‘𝑥)}a.e.𝑀)) | ||
Syntax | cmbfm 29639 | Extend class notation with the measurable functions builder. |
class MblFnM | ||
Definition | df-mbfm 29640* |
Define the measurable function builder, which generates the set of
measurable functions from a measurable space to another one. Here, the
measurable spaces are given using their sigma-algebras 𝑠 and
𝑡,
and the spaces themselves are recovered by ∪ 𝑠 and ∪ 𝑡.
Note the similarities between the definition of measurable functions in measure theory, and of continuous functions in topology. This is the definition for the generic measure theory. For the specific case of functions from ℝ to ℂ, see df-mbf 23194. (Contributed by Thierry Arnoux, 23-Jan-2017.) |
⊢ MblFnM = (𝑠 ∈ ∪ ran sigAlgebra, 𝑡 ∈ ∪ ran sigAlgebra ↦ {𝑓 ∈ (∪ 𝑡 ↑𝑚 ∪ 𝑠) ∣ ∀𝑥 ∈ 𝑡 (◡𝑓 “ 𝑥) ∈ 𝑠}) | ||
Theorem | ismbfm 29641* | The predicate "𝐹 is a measurable function from the measurable space 𝑆 to the measurable space 𝑇". Cf. ismbf 23203. (Contributed by Thierry Arnoux, 23-Jan-2017.) |
⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) ⇒ ⊢ (𝜑 → (𝐹 ∈ (𝑆MblFnM𝑇) ↔ (𝐹 ∈ (∪ 𝑇 ↑𝑚 ∪ 𝑆) ∧ ∀𝑥 ∈ 𝑇 (◡𝐹 “ 𝑥) ∈ 𝑆))) | ||
Theorem | elunirnmbfm 29642* | The property of being a measurable function. (Contributed by Thierry Arnoux, 23-Jan-2017.) |
⊢ (𝐹 ∈ ∪ ran MblFnM ↔ ∃𝑠 ∈ ∪ ran sigAlgebra∃𝑡 ∈ ∪ ran sigAlgebra(𝐹 ∈ (∪ 𝑡 ↑𝑚 ∪ 𝑠) ∧ ∀𝑥 ∈ 𝑡 (◡𝐹 “ 𝑥) ∈ 𝑠)) | ||
Theorem | mbfmfun 29643 | A measurable function is a function. (Contributed by Thierry Arnoux, 24-Jan-2017.) |
⊢ (𝜑 → 𝐹 ∈ ∪ ran MblFnM) ⇒ ⊢ (𝜑 → Fun 𝐹) | ||
Theorem | mbfmf 29644 | A measurable function as a function with domain and codomain. (Contributed by Thierry Arnoux, 25-Jan-2017.) |
⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝐹 ∈ (𝑆MblFnM𝑇)) ⇒ ⊢ (𝜑 → 𝐹:∪ 𝑆⟶∪ 𝑇) | ||
Theorem | isanmbfm 29645 | The predicate to be a measurable function. (Contributed by Thierry Arnoux, 30-Jan-2017.) |
⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝐹 ∈ (𝑆MblFnM𝑇)) ⇒ ⊢ (𝜑 → 𝐹 ∈ ∪ ran MblFnM) | ||
Theorem | mbfmcnvima 29646 | The preimage by a measurable function is a measurable set. (Contributed by Thierry Arnoux, 23-Jan-2017.) |
⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝐹 ∈ (𝑆MblFnM𝑇)) & ⊢ (𝜑 → 𝐴 ∈ 𝑇) ⇒ ⊢ (𝜑 → (◡𝐹 “ 𝐴) ∈ 𝑆) | ||
Theorem | mbfmbfm 29647 | A measurable function to a Borel Set is measurable. (Contributed by Thierry Arnoux, 24-Jan-2017.) |
⊢ (𝜑 → 𝑀 ∈ ∪ ran measures) & ⊢ (𝜑 → 𝐽 ∈ Top) & ⊢ (𝜑 → 𝐹 ∈ (dom 𝑀MblFnM(sigaGen‘𝐽))) ⇒ ⊢ (𝜑 → 𝐹 ∈ ∪ ran MblFnM) | ||
Theorem | mbfmcst 29648* | A constant function is measurable. Cf. mbfconst 23208. (Contributed by Thierry Arnoux, 26-Jan-2017.) |
⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝐹 = (𝑥 ∈ ∪ 𝑆 ↦ 𝐴)) & ⊢ (𝜑 → 𝐴 ∈ ∪ 𝑇) ⇒ ⊢ (𝜑 → 𝐹 ∈ (𝑆MblFnM𝑇)) | ||
Theorem | 1stmbfm 29649 | The first projection map is measurable with regard to the product sigma-algebra. (Contributed by Thierry Arnoux, 3-Jun-2017.) |
⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) ⇒ ⊢ (𝜑 → (1st ↾ (∪ 𝑆 × ∪ 𝑇)) ∈ ((𝑆 ×s 𝑇)MblFnM𝑆)) | ||
Theorem | 2ndmbfm 29650 | The second projection map is measurable with regard to the product sigma-algebra. (Contributed by Thierry Arnoux, 3-Jun-2017.) |
⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) ⇒ ⊢ (𝜑 → (2nd ↾ (∪ 𝑆 × ∪ 𝑇)) ∈ ((𝑆 ×s 𝑇)MblFnM𝑇)) | ||
Theorem | imambfm 29651* | If the sigma-algebra in the range of a given function is generated by a collection of basic sets 𝐾, then to check the measurability of that function, we need only consider inverse images of basic sets 𝑎. (Contributed by Thierry Arnoux, 4-Jun-2017.) |
⊢ (𝜑 → 𝐾 ∈ V) & ⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 = (sigaGen‘𝐾)) ⇒ ⊢ (𝜑 → (𝐹 ∈ (𝑆MblFnM𝑇) ↔ (𝐹:∪ 𝑆⟶∪ 𝑇 ∧ ∀𝑎 ∈ 𝐾 (◡𝐹 “ 𝑎) ∈ 𝑆))) | ||
Theorem | cnmbfm 29652 | A continuous function is measurable with respect to the Borel Algebra of its domain and range. (Contributed by Thierry Arnoux, 3-Jun-2017.) |
⊢ (𝜑 → 𝐹 ∈ (𝐽 Cn 𝐾)) & ⊢ (𝜑 → 𝑆 = (sigaGen‘𝐽)) & ⊢ (𝜑 → 𝑇 = (sigaGen‘𝐾)) ⇒ ⊢ (𝜑 → 𝐹 ∈ (𝑆MblFnM𝑇)) | ||
Theorem | mbfmco 29653 | The composition of two measurable functions is measurable. ( cf. cnmpt11 21276) (Contributed by Thierry Arnoux, 4-Jun-2017.) |
⊢ (𝜑 → 𝑅 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝐹 ∈ (𝑅MblFnM𝑆)) & ⊢ (𝜑 → 𝐺 ∈ (𝑆MblFnM𝑇)) ⇒ ⊢ (𝜑 → (𝐺 ∘ 𝐹) ∈ (𝑅MblFnM𝑇)) | ||
Theorem | mbfmco2 29654* | The pair building of two measurable functions is measurable. ( cf. cnmpt1t 21278). (Contributed by Thierry Arnoux, 6-Jun-2017.) |
⊢ (𝜑 → 𝑅 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑆 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝑇 ∈ ∪ ran sigAlgebra) & ⊢ (𝜑 → 𝐹 ∈ (𝑅MblFnM𝑆)) & ⊢ (𝜑 → 𝐺 ∈ (𝑅MblFnM𝑇)) & ⊢ 𝐻 = (𝑥 ∈ ∪ 𝑅 ↦ 〈(𝐹‘𝑥), (𝐺‘𝑥)〉) ⇒ ⊢ (𝜑 → 𝐻 ∈ (𝑅MblFnM(𝑆 ×s 𝑇))) | ||
Theorem | mbfmvolf 29655 | Measurable functions with respect to the Lebesgue measure are real-valued functions on the real numbers. (Contributed by Thierry Arnoux, 27-Mar-2017.) |
⊢ (𝐹 ∈ (dom volMblFnM𝔅ℝ) → 𝐹:ℝ⟶ℝ) | ||
Theorem | elmbfmvol2 29656 | Measurable functions with respect to the Lebesgue measure. We only have the inclusion, since MblFn includes complex-valued functions. (Contributed by Thierry Arnoux, 26-Jan-2017.) |
⊢ (𝐹 ∈ (dom volMblFnM𝔅ℝ) → 𝐹 ∈ MblFn) | ||
Theorem | mbfmcnt 29657 | All functions are measurable with respect to the counting measure. (Contributed by Thierry Arnoux, 24-Jan-2017.) |
⊢ (𝑂 ∈ 𝑉 → (𝒫 𝑂MblFnM𝔅ℝ) = (ℝ ↑𝑚 𝑂)) | ||
Theorem | br2base 29658* | The base set for the generator of the Borel sigma-algebra on (ℝ × ℝ) is indeed (ℝ × ℝ). (Contributed by Thierry Arnoux, 22-Sep-2017.) |
⊢ ∪ ran (𝑥 ∈ 𝔅ℝ, 𝑦 ∈ 𝔅ℝ ↦ (𝑥 × 𝑦)) = (ℝ × ℝ) | ||
Theorem | dya2ub 29659 | An upper bound for a dyadic number. (Contributed by Thierry Arnoux, 19-Sep-2017.) |
⊢ (𝑅 ∈ ℝ+ → (1 / (2↑(⌊‘(1 − (2 logb 𝑅))))) < 𝑅) | ||
Theorem | sxbrsigalem0 29660* | The closed half-spaces of (ℝ × ℝ) cover (ℝ × ℝ). (Contributed by Thierry Arnoux, 11-Oct-2017.) |
⊢ ∪ (ran (𝑒 ∈ ℝ ↦ ((𝑒[,)+∞) × ℝ)) ∪ ran (𝑓 ∈ ℝ ↦ (ℝ × (𝑓[,)+∞)))) = (ℝ × ℝ) | ||
Theorem | sxbrsigalem3 29661* | The sigma-algebra generated by the closed half-spaces of (ℝ × ℝ) is a subset of the sigma-algebra generated by the closed sets of (ℝ × ℝ). (Contributed by Thierry Arnoux, 11-Oct-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) ⇒ ⊢ (sigaGen‘(ran (𝑒 ∈ ℝ ↦ ((𝑒[,)+∞) × ℝ)) ∪ ran (𝑓 ∈ ℝ ↦ (ℝ × (𝑓[,)+∞))))) ⊆ (sigaGen‘(Clsd‘(𝐽 ×t 𝐽))) | ||
Theorem | dya2iocival 29662* | The function 𝐼 returns closed-below open-above dyadic rational intervals covering the real line. This is the same construction as in dyadmbl 23174. (Contributed by Thierry Arnoux, 24-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) ⇒ ⊢ ((𝑁 ∈ ℤ ∧ 𝑋 ∈ ℤ) → (𝑋𝐼𝑁) = ((𝑋 / (2↑𝑁))[,)((𝑋 + 1) / (2↑𝑁)))) | ||
Theorem | dya2iocress 29663* | Dyadic intervals are subsets of ℝ. (Contributed by Thierry Arnoux, 18-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) ⇒ ⊢ ((𝑁 ∈ ℤ ∧ 𝑋 ∈ ℤ) → (𝑋𝐼𝑁) ⊆ ℝ) | ||
Theorem | dya2iocbrsiga 29664* | Dyadic intervals are Borel sets of ℝ. (Contributed by Thierry Arnoux, 22-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) ⇒ ⊢ ((𝑁 ∈ ℤ ∧ 𝑋 ∈ ℤ) → (𝑋𝐼𝑁) ∈ 𝔅ℝ) | ||
Theorem | dya2icobrsiga 29665* | Dyadic intervals are Borel sets of ℝ. (Contributed by Thierry Arnoux, 22-Sep-2017.) (Revised by Thierry Arnoux, 13-Oct-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) ⇒ ⊢ ran 𝐼 ⊆ 𝔅ℝ | ||
Theorem | dya2icoseg 29666* | For any point and any closed-below, open-above interval of ℝ centered on that point, there is a closed-below open-above dyadic rational interval which contains that point and is included in the original interval. (Contributed by Thierry Arnoux, 19-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑁 = (⌊‘(1 − (2 logb 𝐷))) ⇒ ⊢ ((𝑋 ∈ ℝ ∧ 𝐷 ∈ ℝ+) → ∃𝑏 ∈ ran 𝐼(𝑋 ∈ 𝑏 ∧ 𝑏 ⊆ ((𝑋 − 𝐷)(,)(𝑋 + 𝐷)))) | ||
Theorem | dya2icoseg2 29667* | For any point and any open interval of ℝ containing that point, there is a closed-below open-above dyadic rational interval which contains that point and is included in the original interval. (Contributed by Thierry Arnoux, 12-Oct-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) ⇒ ⊢ ((𝑋 ∈ ℝ ∧ 𝐸 ∈ ran (,) ∧ 𝑋 ∈ 𝐸) → ∃𝑏 ∈ ran 𝐼(𝑋 ∈ 𝑏 ∧ 𝑏 ⊆ 𝐸)) | ||
Theorem | dya2iocrfn 29668* | The function returning dyadic square covering for a given size has domain (ran 𝐼 × ran 𝐼). (Contributed by Thierry Arnoux, 19-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ 𝑅 Fn (ran 𝐼 × ran 𝐼) | ||
Theorem | dya2iocct 29669* | The dyadic rectangle set is countable. (Contributed by Thierry Arnoux, 18-Sep-2017.) (Revised by Thierry Arnoux, 11-Oct-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ ran 𝑅 ≼ ω | ||
Theorem | dya2iocnrect 29670* | For any point of an open rectangle in (ℝ × ℝ), there is a closed-below open-above dyadic rational square which contains that point and is included in the rectangle. (Contributed by Thierry Arnoux, 12-Oct-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) & ⊢ 𝐵 = ran (𝑒 ∈ ran (,), 𝑓 ∈ ran (,) ↦ (𝑒 × 𝑓)) ⇒ ⊢ ((𝑋 ∈ (ℝ × ℝ) ∧ 𝐴 ∈ 𝐵 ∧ 𝑋 ∈ 𝐴) → ∃𝑏 ∈ ran 𝑅(𝑋 ∈ 𝑏 ∧ 𝑏 ⊆ 𝐴)) | ||
Theorem | dya2iocnei 29671* | For any point of an open set of the usual topology on (ℝ × ℝ) there is a closed-below open-above dyadic rational square which contains that point and is entirely in the open set. (Contributed by Thierry Arnoux, 21-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ ((𝐴 ∈ (𝐽 ×t 𝐽) ∧ 𝑋 ∈ 𝐴) → ∃𝑏 ∈ ran 𝑅(𝑋 ∈ 𝑏 ∧ 𝑏 ⊆ 𝐴)) | ||
Theorem | dya2iocuni 29672* | Every open set of (ℝ × ℝ) is a union of closed-below open-above dyadic rational rectangular subsets of (ℝ × ℝ). This union must be a countable union by dya2iocct 29669. (Contributed by Thierry Arnoux, 18-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ (𝐴 ∈ (𝐽 ×t 𝐽) → ∃𝑐 ∈ 𝒫 ran 𝑅∪ 𝑐 = 𝐴) | ||
Theorem | dya2iocucvr 29673* | The dyadic rectangular set collection covers (ℝ × ℝ). (Contributed by Thierry Arnoux, 18-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ ∪ ran 𝑅 = (ℝ × ℝ) | ||
Theorem | sxbrsigalem1 29674* | The Borel algebra on (ℝ × ℝ) is a subset of the sigma-algebra generated by the dyadic closed-below, open-above rectangular subsets of (ℝ × ℝ). This is a step of the proof of Proposition 1.1.5 of [Cohn] p. 4. (Contributed by Thierry Arnoux, 17-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ (sigaGen‘(𝐽 ×t 𝐽)) ⊆ (sigaGen‘ran 𝑅) | ||
Theorem | sxbrsigalem2 29675* | The sigma-algebra generated by the dyadic closed-below, open-above rectangular subsets of (ℝ × ℝ) is a subset of the sigma-algebra generated by the closed half-spaces of (ℝ × ℝ). The proof goes by noting the fact that the dyadic rectangles are intersections of a 'vertical band' and an 'horizontal band', which themselves are differences of closed half-spaces. (Contributed by Thierry Arnoux, 17-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ (sigaGen‘ran 𝑅) ⊆ (sigaGen‘(ran (𝑒 ∈ ℝ ↦ ((𝑒[,)+∞) × ℝ)) ∪ ran (𝑓 ∈ ℝ ↦ (ℝ × (𝑓[,)+∞))))) | ||
Theorem | sxbrsigalem4 29676* | The Borel algebra on (ℝ × ℝ) is generated by the dyadic closed-below, open-above rectangular subsets of (ℝ × ℝ). Proposition 1.1.5 of [Cohn] p. 4 . Note that the interval used in this formalization are closed-below, open-above instead of open-below, closed-above in the proof as they are ultimately generated by the floor function. (Contributed by Thierry Arnoux, 21-Sep-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ (sigaGen‘(𝐽 ×t 𝐽)) = (sigaGen‘ran 𝑅) | ||
Theorem | sxbrsigalem5 29677* | First direction for sxbrsiga 29679. (Contributed by Thierry Arnoux, 22-Sep-2017.) (Revised by Thierry Arnoux, 11-Oct-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) & ⊢ 𝐼 = (𝑥 ∈ ℤ, 𝑛 ∈ ℤ ↦ ((𝑥 / (2↑𝑛))[,)((𝑥 + 1) / (2↑𝑛)))) & ⊢ 𝑅 = (𝑢 ∈ ran 𝐼, 𝑣 ∈ ran 𝐼 ↦ (𝑢 × 𝑣)) ⇒ ⊢ (sigaGen‘(𝐽 ×t 𝐽)) ⊆ (𝔅ℝ ×s 𝔅ℝ) | ||
Theorem | sxbrsigalem6 29678 | First direction for sxbrsiga 29679, same as sxbrsigalem6, dealing with the antecedents. (Contributed by Thierry Arnoux, 10-Oct-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) ⇒ ⊢ (sigaGen‘(𝐽 ×t 𝐽)) ⊆ (𝔅ℝ ×s 𝔅ℝ) | ||
Theorem | sxbrsiga 29679 | The product sigma-algebra (𝔅ℝ ×s 𝔅ℝ) is the Borel algebra on (ℝ × ℝ) See example 5.1.1 of [Cohn] p. 143 . (Contributed by Thierry Arnoux, 10-Oct-2017.) |
⊢ 𝐽 = (topGen‘ran (,)) ⇒ ⊢ (𝔅ℝ ×s 𝔅ℝ) = (sigaGen‘(𝐽 ×t 𝐽)) | ||
In this section, we define a function toOMeas which constructs an outer measure, from a pre-measure 𝑅. An explicit generic definition of an outer measure is not given. It consists of the three following statements: - the outer measure of an empty set is zero (oms0 29686) - it is monotone (omsmon 29687) - it is countably sub-additive (omssubadd 29689) See Definition 1.11.1 of [Bogachev] p. 41. | ||
Syntax | coms 29680 | Class declaration for the outer measure construction function. |
class toOMeas | ||
Definition | df-oms 29681* | Define a function constructing an outer measure. See omsval 29682 for its value. Definition 1.5 of [Bogachev] p. 16. (Contributed by Thierry Arnoux, 15-Sep-2019.) (Revised by AV, 4-Oct-2020.) |
⊢ toOMeas = (𝑟 ∈ V ↦ (𝑎 ∈ 𝒫 ∪ dom 𝑟 ↦ inf(ran (𝑥 ∈ {𝑧 ∈ 𝒫 dom 𝑟 ∣ (𝑎 ⊆ ∪ 𝑧 ∧ 𝑧 ≼ ω)} ↦ Σ*𝑦 ∈ 𝑥(𝑟‘𝑦)), (0[,]+∞), < ))) | ||
Theorem | omsval 29682* | Value of the function mapping a content function to the corresponding outer measure. (Contributed by Thierry Arnoux, 15-Sep-2019.) (Revised by AV, 4-Oct-2020.) |
⊢ (𝑅 ∈ V → (toOMeas‘𝑅) = (𝑎 ∈ 𝒫 ∪ dom 𝑅 ↦ inf(ran (𝑥 ∈ {𝑧 ∈ 𝒫 dom 𝑅 ∣ (𝑎 ⊆ ∪ 𝑧 ∧ 𝑧 ≼ ω)} ↦ Σ*𝑦 ∈ 𝑥(𝑅‘𝑦)), (0[,]+∞), < ))) | ||
Theorem | omsfval 29683* | Value of the outer measure evaluated for a given set 𝐴. (Contributed by Thierry Arnoux, 15-Sep-2019.) (Revised by AV, 4-Oct-2020.) |
⊢ ((𝑄 ∈ 𝑉 ∧ 𝑅:𝑄⟶(0[,]+∞) ∧ 𝐴 ⊆ ∪ 𝑄) → ((toOMeas‘𝑅)‘𝐴) = inf(ran (𝑥 ∈ {𝑧 ∈ 𝒫 dom 𝑅 ∣ (𝐴 ⊆ ∪ 𝑧 ∧ 𝑧 ≼ ω)} ↦ Σ*𝑦 ∈ 𝑥(𝑅‘𝑦)), (0[,]+∞), < )) | ||
Theorem | omscl 29684* | A closure lemma for the constructed outer measure. (Contributed by Thierry Arnoux, 17-Sep-2019.) |
⊢ ((𝑄 ∈ 𝑉 ∧ 𝑅:𝑄⟶(0[,]+∞) ∧ 𝐴 ∈ 𝒫 ∪ dom 𝑅) → ran (𝑥 ∈ {𝑧 ∈ 𝒫 dom 𝑅 ∣ (𝐴 ⊆ ∪ 𝑧 ∧ 𝑧 ≼ ω)} ↦ Σ*𝑦 ∈ 𝑥(𝑅‘𝑦)) ⊆ (0[,]+∞)) | ||
Theorem | omsf 29685 | A constructed outer measure is a function. (Contributed by Thierry Arnoux, 17-Sep-2019.) (Revised by AV, 4-Oct-2020.) |
⊢ ((𝑄 ∈ 𝑉 ∧ 𝑅:𝑄⟶(0[,]+∞)) → (toOMeas‘𝑅):𝒫 ∪ dom 𝑅⟶(0[,]+∞)) | ||
Theorem | oms0 29686 | A constructed outer measure evaluates to zero for the empty set. (Contributed by Thierry Arnoux, 15-Sep-2019.) (Revised by AV, 4-Oct-2020.) |
⊢ 𝑀 = (toOMeas‘𝑅) & ⊢ (𝜑 → 𝑄 ∈ 𝑉) & ⊢ (𝜑 → 𝑅:𝑄⟶(0[,]+∞)) & ⊢ (𝜑 → ∅ ∈ dom 𝑅) & ⊢ (𝜑 → (𝑅‘∅) = 0) ⇒ ⊢ (𝜑 → (𝑀‘∅) = 0) | ||
Theorem | omsmon 29687 | A constructed outer measure is monotone. Note in Example 1.5.2 of [Bogachev] p. 17. (Contributed by Thierry Arnoux, 15-Sep-2019.) (Revised by AV, 4-Oct-2020.) |
⊢ 𝑀 = (toOMeas‘𝑅) & ⊢ (𝜑 → 𝑄 ∈ 𝑉) & ⊢ (𝜑 → 𝑅:𝑄⟶(0[,]+∞)) & ⊢ (𝜑 → 𝐴 ⊆ 𝐵) & ⊢ (𝜑 → 𝐵 ⊆ ∪ 𝑄) ⇒ ⊢ (𝜑 → (𝑀‘𝐴) ≤ (𝑀‘𝐵)) | ||
Theorem | omssubaddlem 29688* | For any small margin 𝐸, we can find a covering approaching the outer measure of a set 𝐴 by that margin. (Contributed by Thierry Arnoux, 18-Sep-2019.) (Revised by AV, 4-Oct-2020.) |
⊢ 𝑀 = (toOMeas‘𝑅) & ⊢ (𝜑 → 𝑄 ∈ 𝑉) & ⊢ (𝜑 → 𝑅:𝑄⟶(0[,]+∞)) & ⊢ (𝜑 → 𝐴 ⊆ ∪ 𝑄) & ⊢ (𝜑 → (𝑀‘𝐴) ∈ ℝ) & ⊢ (𝜑 → 𝐸 ∈ ℝ+) ⇒ ⊢ (𝜑 → ∃𝑥 ∈ {𝑧 ∈ 𝒫 dom 𝑅 ∣ (𝐴 ⊆ ∪ 𝑧 ∧ 𝑧 ≼ ω)}Σ*𝑤 ∈ 𝑥(𝑅‘𝑤) < ((𝑀‘𝐴) + 𝐸)) | ||
Theorem | omssubadd 29689* | A constructed outer measure is countably sub-additive. Lemma 1.5.4 of [Bogachev] p. 17. (Contributed by Thierry Arnoux, 21-Sep-2019.) (Revised by AV, 4-Oct-2020.) |
⊢ 𝑀 = (toOMeas‘𝑅) & ⊢ (𝜑 → 𝑄 ∈ 𝑉) & ⊢ (𝜑 → 𝑅:𝑄⟶(0[,]+∞)) & ⊢ ((𝜑 ∧ 𝑦 ∈ 𝑋) → 𝐴 ⊆ ∪ 𝑄) & ⊢ (𝜑 → 𝑋 ≼ ω) ⇒ ⊢ (𝜑 → (𝑀‘∪ 𝑦 ∈ 𝑋 𝐴) ≤ Σ*𝑦 ∈ 𝑋(𝑀‘𝐴)) | ||
Syntax | ccarsg 29690 | Class declaration for the Caratheodory sigma-Algebra construction. |
class toCaraSiga | ||
Definition | df-carsg 29691* | Define a function constructing Caratheodory measurable sets for a given outer measure. See carsgval 29692 for its value. Definition 1.11.2 of [Bogachev] p. 41. (Contributed by Thierry Arnoux, 17-May-2020.) |
⊢ toCaraSiga = (𝑚 ∈ V ↦ {𝑎 ∈ 𝒫 ∪ dom 𝑚 ∣ ∀𝑒 ∈ 𝒫 ∪ dom 𝑚((𝑚‘(𝑒 ∩ 𝑎)) +𝑒 (𝑚‘(𝑒 ∖ 𝑎))) = (𝑚‘𝑒)}) | ||
Theorem | carsgval 29692* | Value of the Caratheodory sigma-Algebra construction function. (Contributed by Thierry Arnoux, 17-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) ⇒ ⊢ (𝜑 → (toCaraSiga‘𝑀) = {𝑎 ∈ 𝒫 𝑂 ∣ ∀𝑒 ∈ 𝒫 𝑂((𝑀‘(𝑒 ∩ 𝑎)) +𝑒 (𝑀‘(𝑒 ∖ 𝑎))) = (𝑀‘𝑒)}) | ||
Theorem | carsgcl 29693 | Closure of the Caratheodory measurable sets. (Contributed by Thierry Arnoux, 17-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) ⇒ ⊢ (𝜑 → (toCaraSiga‘𝑀) ⊆ 𝒫 𝑂) | ||
Theorem | elcarsg 29694* | Property of being a Catatheodory measurable set. (Contributed by Thierry Arnoux, 17-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) ⇒ ⊢ (𝜑 → (𝐴 ∈ (toCaraSiga‘𝑀) ↔ (𝐴 ⊆ 𝑂 ∧ ∀𝑒 ∈ 𝒫 𝑂((𝑀‘(𝑒 ∩ 𝐴)) +𝑒 (𝑀‘(𝑒 ∖ 𝐴))) = (𝑀‘𝑒)))) | ||
Theorem | baselcarsg 29695 | The universe set, 𝑂, is Caratheodory measurable. (Contributed by Thierry Arnoux, 17-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) & ⊢ (𝜑 → (𝑀‘∅) = 0) ⇒ ⊢ (𝜑 → 𝑂 ∈ (toCaraSiga‘𝑀)) | ||
Theorem | 0elcarsg 29696 | The empty set is Caratheodory measurable. (Contributed by Thierry Arnoux, 30-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) & ⊢ (𝜑 → (𝑀‘∅) = 0) ⇒ ⊢ (𝜑 → ∅ ∈ (toCaraSiga‘𝑀)) | ||
Theorem | carsguni 29697 | The union of all Caratheodory measurable sets is the universe. (Contributed by Thierry Arnoux, 22-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) & ⊢ (𝜑 → (𝑀‘∅) = 0) ⇒ ⊢ (𝜑 → ∪ (toCaraSiga‘𝑀) = 𝑂) | ||
Theorem | elcarsgss 29698 | Caratheodory measurable sets are subsets of the universe. (Contributed by Thierry Arnoux, 21-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) & ⊢ (𝜑 → 𝐴 ∈ (toCaraSiga‘𝑀)) ⇒ ⊢ (𝜑 → 𝐴 ⊆ 𝑂) | ||
Theorem | difelcarsg 29699 | The Caratheodory measurable sets are closed under complement. (Contributed by Thierry Arnoux, 17-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) & ⊢ (𝜑 → 𝐴 ∈ (toCaraSiga‘𝑀)) ⇒ ⊢ (𝜑 → (𝑂 ∖ 𝐴) ∈ (toCaraSiga‘𝑀)) | ||
Theorem | inelcarsg 29700* | The Caratheodory measurable sets are closed under intersection. (Contributed by Thierry Arnoux, 18-May-2020.) |
⊢ (𝜑 → 𝑂 ∈ 𝑉) & ⊢ (𝜑 → 𝑀:𝒫 𝑂⟶(0[,]+∞)) & ⊢ (𝜑 → 𝐴 ∈ (toCaraSiga‘𝑀)) & ⊢ ((𝜑 ∧ 𝑎 ∈ 𝒫 𝑂 ∧ 𝑏 ∈ 𝒫 𝑂) → (𝑀‘(𝑎 ∪ 𝑏)) ≤ ((𝑀‘𝑎) +𝑒 (𝑀‘𝑏))) & ⊢ (𝜑 → 𝐵 ∈ (toCaraSiga‘𝑀)) ⇒ ⊢ (𝜑 → (𝐴 ∩ 𝐵) ∈ (toCaraSiga‘𝑀)) |
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