Theorem omecl 42775

Description: The outer measure of a set is a nonnegative extended real. (Contributed by Glauco Siliprandi, 17-Aug-2020.)

Hypotheses

Ref	Expression
omecl.o	⊢ (𝜑 → 𝑂 ∈ OutMeas)
omecl.x	⊢ 𝑋 = ∪ dom 𝑂
omecl.ss	⊢ (𝜑 → 𝐴 ⊆ 𝑋)

Assertion

Ref	Expression
omecl	⊢ (𝜑 → (𝑂‘𝐴) ∈ (0[,]+∞))

Proof of Theorem omecl

Step	Hyp	Ref	Expression
1		omecl.o	. . 3 ⊢ (𝜑 → 𝑂 ∈ OutMeas)
2		omecl.x	. . 3 ⊢ 𝑋 = ∪ dom 𝑂
3	1, 2	omef 42768	. 2 ⊢ (𝜑 → 𝑂:𝒫 𝑋⟶(0[,]+∞))
4		omecl.ss	. . 3 ⊢ (𝜑 → 𝐴 ⊆ 𝑋)
5	2	a1i 11	. . . . . 6 ⊢ (𝜑 → 𝑋 = ∪ dom 𝑂)
6	1	dmexd 7607	. . . . . . 7 ⊢ (𝜑 → dom 𝑂 ∈ V)
7	6	uniexd 7460	. . . . . 6 ⊢ (𝜑 → ∪ dom 𝑂 ∈ V)
8	5, 7	eqeltrd 2911	. . . . 5 ⊢ (𝜑 → 𝑋 ∈ V)
9	8, 4	ssexd 5219	. . . 4 ⊢ (𝜑 → 𝐴 ∈ V)
10		elpwg 4543	. . . 4 ⊢ (𝐴 ∈ V → (𝐴 ∈ 𝒫 𝑋 ↔ 𝐴 ⊆ 𝑋))
11	9, 10	syl 17	. . 3 ⊢ (𝜑 → (𝐴 ∈ 𝒫 𝑋 ↔ 𝐴 ⊆ 𝑋))
12	4, 11	mpbird 259	. 2 ⊢ (𝜑 → 𝐴 ∈ 𝒫 𝑋)
13	3, 12	ffvelrnd 6845	1 ⊢ (𝜑 → (𝑂‘𝐴) ∈ (0[,]+∞))

Syntax hints:   → wi 4   ↔ wb 208   = wceq 1531   ∈ wcel 2108  Vcvv 3493   ⊆ wss 3934  𝒫 cpw 4537  ∪ cuni 4830  dom cdm 5548  ‘cfv 6348  (class class class)co 7148  0cc0 10529  +∞cpnf 10664  [,]cicc 12733  OutMeascome 42761

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1790  ax-4 1804  ax-5 1905  ax-6 1964  ax-7 2009  ax-8 2110  ax-9 2118  ax-10 2139  ax-11 2154  ax-12 2170  ax-ext 2791  ax-sep 5194  ax-nul 5201  ax-pr 5320  ax-un 7453

This theorem depends on definitions:  df-bi 209  df-an 399  df-or 844  df-3an 1084  df-tru 1534  df-ex 1775  df-nf 1779  df-sb 2064  df-mo 2616  df-eu 2648  df-clab 2798  df-cleq 2812  df-clel 2891  df-nfc 2961  df-ral 3141  df-rex 3142  df-rab 3145  df-v 3495  df-sbc 3771  df-dif 3937  df-un 3939  df-in 3941  df-ss 3950  df-nul 4290  df-if 4466  df-pw 4539  df-sn 4560  df-pr 4562  df-op 4566  df-uni 4831  df-br 5058  df-opab 5120  df-id 5453  df-xp 5554  df-rel 5555  df-cnv 5556  df-co 5557  df-dm 5558  df-rn 5559  df-res 5560  df-iota 6307  df-fun 6350  df-fn 6351  df-f 6352  df-fv 6356  df-ome 42762

This theorem is referenced by:  caragen0  42778  omexrcl  42779  caragenunidm  42780  omessre  42782  caragenuncllem  42784  caragendifcl  42786  omeunle  42788  omeiunle  42789  omeiunltfirp  42791  carageniuncllem2  42794  carageniuncl  42795  caratheodorylem1  42798  caratheodorylem2  42799  omege0  42805