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Theorem measbase 30388
Description: The base set of a measure is a sigma-algebra. (Contributed by Thierry Arnoux, 25-Dec-2016.)
Assertion
Ref Expression
measbase (𝑀 ∈ (measures‘𝑆) → 𝑆 ran sigAlgebra)

Proof of Theorem measbase
Dummy variables 𝑥 𝑚 𝑦 𝑠 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 elfvdm 6258 . 2 (𝑀 ∈ (measures‘𝑆) → 𝑆 ∈ dom measures)
2 vex 3234 . . . . 5 𝑠 ∈ V
3 ovex 6718 . . . . 5 (0[,]+∞) ∈ V
4 mapex 7905 . . . . 5 ((𝑠 ∈ V ∧ (0[,]+∞) ∈ V) → {𝑚𝑚:𝑠⟶(0[,]+∞)} ∈ V)
52, 3, 4mp2an 708 . . . 4 {𝑚𝑚:𝑠⟶(0[,]+∞)} ∈ V
6 simp1 1081 . . . . 5 ((𝑚:𝑠⟶(0[,]+∞) ∧ (𝑚‘∅) = 0 ∧ ∀𝑥 ∈ 𝒫 𝑠((𝑥 ≼ ω ∧ Disj 𝑦𝑥 𝑦) → (𝑚 𝑥) = Σ*𝑦𝑥(𝑚𝑦))) → 𝑚:𝑠⟶(0[,]+∞))
76ss2abi 3707 . . . 4 {𝑚 ∣ (𝑚:𝑠⟶(0[,]+∞) ∧ (𝑚‘∅) = 0 ∧ ∀𝑥 ∈ 𝒫 𝑠((𝑥 ≼ ω ∧ Disj 𝑦𝑥 𝑦) → (𝑚 𝑥) = Σ*𝑦𝑥(𝑚𝑦)))} ⊆ {𝑚𝑚:𝑠⟶(0[,]+∞)}
85, 7ssexi 4836 . . 3 {𝑚 ∣ (𝑚:𝑠⟶(0[,]+∞) ∧ (𝑚‘∅) = 0 ∧ ∀𝑥 ∈ 𝒫 𝑠((𝑥 ≼ ω ∧ Disj 𝑦𝑥 𝑦) → (𝑚 𝑥) = Σ*𝑦𝑥(𝑚𝑦)))} ∈ V
9 df-meas 30387 . . 3 measures = (𝑠 ran sigAlgebra ↦ {𝑚 ∣ (𝑚:𝑠⟶(0[,]+∞) ∧ (𝑚‘∅) = 0 ∧ ∀𝑥 ∈ 𝒫 𝑠((𝑥 ≼ ω ∧ Disj 𝑦𝑥 𝑦) → (𝑚 𝑥) = Σ*𝑦𝑥(𝑚𝑦)))})
108, 9dmmpti 6061 . 2 dom measures = ran sigAlgebra
111, 10syl6eleq 2740 1 (𝑀 ∈ (measures‘𝑆) → 𝑆 ran sigAlgebra)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 383  w3a 1054   = wceq 1523  wcel 2030  {cab 2637  wral 2941  Vcvv 3231  c0 3948  𝒫 cpw 4191   cuni 4468  Disj wdisj 4652   class class class wbr 4685  dom cdm 5143  ran crn 5144  wf 5922  cfv 5926  (class class class)co 6690  ωcom 7107  cdom 7995  0cc0 9974  +∞cpnf 10109  [,]cicc 12216  Σ*cesum 30217  sigAlgebracsiga 30298  measurescmeas 30386
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1762  ax-4 1777  ax-5 1879  ax-6 1945  ax-7 1981  ax-8 2032  ax-9 2039  ax-10 2059  ax-11 2074  ax-12 2087  ax-13 2282  ax-ext 2631  ax-sep 4814  ax-nul 4822  ax-pow 4873  ax-pr 4936  ax-un 6991
This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-3an 1056  df-tru 1526  df-ex 1745  df-nf 1750  df-sb 1938  df-eu 2502  df-mo 2503  df-clab 2638  df-cleq 2644  df-clel 2647  df-nfc 2782  df-ne 2824  df-ral 2946  df-rex 2947  df-rab 2950  df-v 3233  df-sbc 3469  df-dif 3610  df-un 3612  df-in 3614  df-ss 3621  df-nul 3949  df-if 4120  df-pw 4193  df-sn 4211  df-pr 4213  df-op 4217  df-uni 4469  df-br 4686  df-opab 4746  df-mpt 4763  df-id 5053  df-xp 5149  df-rel 5150  df-cnv 5151  df-co 5152  df-dm 5153  df-rn 5154  df-iota 5889  df-fun 5928  df-fn 5929  df-f 5930  df-fv 5934  df-ov 6693  df-meas 30387
This theorem is referenced by:  measfrge0  30394  measvnul  30397  measvun  30400  measxun2  30401  measun  30402  measvuni  30405  measssd  30406  measunl  30407  measiuns  30408  measiun  30409  meascnbl  30410  measinblem  30411  measinb  30412  measinb2  30414  measdivcstOLD  30415  measdivcst  30416  aean  30435  mbfmbfm  30448  domprobsiga  30601  prob01  30603  probfinmeasbOLD  30618  probfinmeasb  30619  probmeasb  30620
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