Theorem cndprobval 34847

Description: The value of the conditional probability , i.e. the probability for the event 𝐴, given 𝐵, under the probability law 𝑃. (Contributed by Thierry Arnoux, 21-Jan-2017.)

Assertion

Ref	Expression
cndprobval	⊢ ((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) → ((cprob‘𝑃)‘⟨𝐴, 𝐵⟩) = ((𝑃‘(𝐴 ∩ 𝐵)) / (𝑃‘𝐵)))

Proof of Theorem cndprobval

Dummy variables 𝑎 𝑏 𝑝 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-ov 7419	. 2 ⊢ (𝐴(cprob‘𝑃)𝐵) = ((cprob‘𝑃)‘⟨𝐴, 𝐵⟩)
2		df-cndprob 34846	. . . . 5 ⊢ cprob = (𝑝 ∈ Prob ↦ (𝑎 ∈ dom 𝑝, 𝑏 ∈ dom 𝑝 ↦ ((𝑝‘(𝑎 ∩ 𝑏)) / (𝑝‘𝑏))))
3		dmeq 5895	. . . . . 6 ⊢ (𝑝 = 𝑃 → dom 𝑝 = dom 𝑃)
4		fveq1 6884	. . . . . . 7 ⊢ (𝑝 = 𝑃 → (𝑝‘(𝑎 ∩ 𝑏)) = (𝑃‘(𝑎 ∩ 𝑏)))
5		fveq1 6884	. . . . . . 7 ⊢ (𝑝 = 𝑃 → (𝑝‘𝑏) = (𝑃‘𝑏))
6	4, 5	oveq12d 7434	. . . . . 6 ⊢ (𝑝 = 𝑃 → ((𝑝‘(𝑎 ∩ 𝑏)) / (𝑝‘𝑏)) = ((𝑃‘(𝑎 ∩ 𝑏)) / (𝑃‘𝑏)))
7	3, 3, 6	mpoeq123dv 7491	. . . . 5 ⊢ (𝑝 = 𝑃 → (𝑎 ∈ dom 𝑝, 𝑏 ∈ dom 𝑝 ↦ ((𝑝‘(𝑎 ∩ 𝑏)) / (𝑝‘𝑏))) = (𝑎 ∈ dom 𝑃, 𝑏 ∈ dom 𝑃 ↦ ((𝑃‘(𝑎 ∩ 𝑏)) / (𝑃‘𝑏))))
8		id 23	. . . . 5 ⊢ (𝑃 ∈ Prob → 𝑃 ∈ Prob)
9		dmexg 7900	. . . . . 6 ⊢ (𝑃 ∈ Prob → dom 𝑃 ∈ V)
10		mpoexga 8076	. . . . . 6 ⊢ ((dom 𝑃 ∈ V ∧ dom 𝑃 ∈ V) → (𝑎 ∈ dom 𝑃, 𝑏 ∈ dom 𝑃 ↦ ((𝑃‘(𝑎 ∩ 𝑏)) / (𝑃‘𝑏))) ∈ V)
11	9, 9, 10	syl2anc 596	. . . . 5 ⊢ (𝑃 ∈ Prob → (𝑎 ∈ dom 𝑃, 𝑏 ∈ dom 𝑃 ↦ ((𝑃‘(𝑎 ∩ 𝑏)) / (𝑃‘𝑏))) ∈ V)
12	2, 7, 8, 11	fvmptd3 7017	. . . 4 ⊢ (𝑃 ∈ Prob → (cprob‘𝑃) = (𝑎 ∈ dom 𝑃, 𝑏 ∈ dom 𝑃 ↦ ((𝑃‘(𝑎 ∩ 𝑏)) / (𝑃‘𝑏))))
13	12	3ad2ant1 1151	. . 3 ⊢ ((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) → (cprob‘𝑃) = (𝑎 ∈ dom 𝑃, 𝑏 ∈ dom 𝑃 ↦ ((𝑃‘(𝑎 ∩ 𝑏)) / (𝑃‘𝑏))))
14		simprl 783	. . . . . 6 ⊢ (((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) ∧ (𝑎 = 𝐴 ∧ 𝑏 = 𝐵)) → 𝑎 = 𝐴)
15		simprr 785	. . . . . 6 ⊢ (((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) ∧ (𝑎 = 𝐴 ∧ 𝑏 = 𝐵)) → 𝑏 = 𝐵)
16	14, 15	ineq12d 4174	. . . . 5 ⊢ (((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) ∧ (𝑎 = 𝐴 ∧ 𝑏 = 𝐵)) → (𝑎 ∩ 𝑏) = (𝐴 ∩ 𝐵))
17	16	fveq2d 6889	. . . 4 ⊢ (((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) ∧ (𝑎 = 𝐴 ∧ 𝑏 = 𝐵)) → (𝑃‘(𝑎 ∩ 𝑏)) = (𝑃‘(𝐴 ∩ 𝐵)))
18	15	fveq2d 6889	. . . 4 ⊢ (((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) ∧ (𝑎 = 𝐴 ∧ 𝑏 = 𝐵)) → (𝑃‘𝑏) = (𝑃‘𝐵))
19	17, 18	oveq12d 7434	. . 3 ⊢ (((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) ∧ (𝑎 = 𝐴 ∧ 𝑏 = 𝐵)) → ((𝑃‘(𝑎 ∩ 𝑏)) / (𝑃‘𝑏)) = ((𝑃‘(𝐴 ∩ 𝐵)) / (𝑃‘𝐵)))
20		simp2 1155	. . 3 ⊢ ((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) → 𝐴 ∈ dom 𝑃)
21		simp3 1156	. . 3 ⊢ ((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) → 𝐵 ∈ dom 𝑃)
22		ovexd 7451	. . 3 ⊢ ((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) → ((𝑃‘(𝐴 ∩ 𝐵)) / (𝑃‘𝐵)) ∈ V)
23	13, 19, 20, 21, 22	ovmpod 7568	. 2 ⊢ ((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) → (𝐴(cprob‘𝑃)𝐵) = ((𝑃‘(𝐴 ∩ 𝐵)) / (𝑃‘𝐵)))
24	1, 23	eqtr3id 2814	1 ⊢ ((𝑃 ∈ Prob ∧ 𝐴 ∈ dom 𝑃 ∧ 𝐵 ∈ dom 𝑃) → ((cprob‘𝑃)‘⟨𝐴, 𝐵⟩) = ((𝑃‘(𝐴 ∩ 𝐵)) / (𝑃‘𝐵)))

This proof depends on syntax axioms:   → wi 4   ∧ wa 401   ∧ w3a 1103   = wceq 1570   ∈ wcel 2146  Vcvv 3457   ∩ cin 3905  ⟨cop 4597  dom cdm 5663  ‘cfv 6540  (class class class)co 7416   ∈ cmpo 7418   / cdiv 11882  Probcprb 34821  cprobccprob 34845

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2148  ax-9 2156  ax-10 2179  ax-11 2195  ax-12 2216  ax-ext 2737  ax-rep 5240  ax-sep 5259  ax-nul 5271  ax-pow 5338  ax-pr 5406  ax-un 7738

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2569  df-eu 2599  df-clab 2744  df-cleq 2757  df-clel 2840  df-nfc 2914  df-ne 2961  df-ral 3082  df-rex 3092  df-reu 3372  df-rab 3419  df-v 3459  df-sbc 3747  df-csb 3855  df-dif 3909  df-un 3911  df-in 3913  df-ss 3923  df-nul 4287  df-if 4490  df-pw 4566  df-sn 4592  df-pr 4594  df-op 4598  df-uni 4875  df-iun 4960  df-br 5112  df-opab 5176  df-mpt 5195  df-id 5558  df-xp 5669  df-rel 5670  df-cnv 5671  df-co 5672  df-dm 5673  df-rn 5674  df-res 5675  df-ima 5676  df-iota 6496  df-fun 6542  df-fn 6543  df-f 6544  df-f1 6545  df-fo 6546  df-f1o 6547  df-fv 6548  df-ov 7419  df-oprab 7420  df-mpo 7421  df-1st 7988  df-2nd 7989  df-cndprob 34846

This theorem is used by:  cndprobin  34848  cndprob01  34849  cndprobtot  34850  cndprobnul  34851  cndprobprob  34852