Theorem dmtpos 8235

Description: The domain of tpos 𝐹 when dom 𝐹 is a relation. (Contributed by Mario Carneiro, 10-Sep-2015.)

Assertion

Ref	Expression
dmtpos	⊢ (Rel dom 𝐹 → dom tpos 𝐹 = ◡dom 𝐹)

Proof of Theorem dmtpos

Dummy variables 𝑥 𝑦 𝑧 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		0nelxp 5697	. . . . 5 ⊢ ¬ ∅ ∈ (V × V)
2		ssel 3932	. . . . 5 ⊢ (dom 𝐹 ⊆ (V × V) → (∅ ∈ dom 𝐹 → ∅ ∈ (V × V)))
3	1, 2	mtoi 202	. . . 4 ⊢ (dom 𝐹 ⊆ (V × V) → ¬ ∅ ∈ dom 𝐹)
4		df-rel 5670	. . . 4 ⊢ (Rel dom 𝐹 ↔ dom 𝐹 ⊆ (V × V))
5		reldmtpos 8231	. . . 4 ⊢ (Rel dom tpos 𝐹 ↔ ¬ ∅ ∈ dom 𝐹)
6	3, 4, 5	3imtr4i 295	. . 3 ⊢ (Rel dom 𝐹 → Rel dom tpos 𝐹)
7		relcnv 6108	. . 3 ⊢ Rel ◡dom 𝐹
8	6, 7	jctir 529	. 2 ⊢ (Rel dom 𝐹 → (Rel dom tpos 𝐹 ∧ Rel ◡dom 𝐹))
9		vex 3459	. . . . . 6 ⊢ 𝑧 ∈ V
10		brtpos 8232	. . . . . 6 ⊢ (𝑧 ∈ V → (⟨𝑥, 𝑦⟩tpos 𝐹𝑧 ↔ ⟨𝑦, 𝑥⟩𝐹𝑧))
11	9, 10	mp1i 14	. . . . 5 ⊢ (Rel dom 𝐹 → (⟨𝑥, 𝑦⟩tpos 𝐹𝑧 ↔ ⟨𝑦, 𝑥⟩𝐹𝑧))
12	11	exbidv 1951	. . . 4 ⊢ (Rel dom 𝐹 → (∃𝑧⟨𝑥, 𝑦⟩tpos 𝐹𝑧 ↔ ∃𝑧⟨𝑦, 𝑥⟩𝐹𝑧))
13		opex 5447	. . . . 5 ⊢ ⟨𝑥, 𝑦⟩ ∈ V
14	13	eldm 5892	. . . 4 ⊢ (⟨𝑥, 𝑦⟩ ∈ dom tpos 𝐹 ↔ ∃𝑧⟨𝑥, 𝑦⟩tpos 𝐹𝑧)
15		vex 3459	. . . . . 6 ⊢ 𝑥 ∈ V
16		vex 3459	. . . . . 6 ⊢ 𝑦 ∈ V
17	15, 16	opelcnv 5869	. . . . 5 ⊢ (⟨𝑥, 𝑦⟩ ∈ ◡dom 𝐹 ↔ ⟨𝑦, 𝑥⟩ ∈ dom 𝐹)
18		opex 5447	. . . . . 6 ⊢ ⟨𝑦, 𝑥⟩ ∈ V
19	18	eldm 5892	. . . . 5 ⊢ (⟨𝑦, 𝑥⟩ ∈ dom 𝐹 ↔ ∃𝑧⟨𝑦, 𝑥⟩𝐹𝑧)
20	17, 19	bitri 278	. . . 4 ⊢ (⟨𝑥, 𝑦⟩ ∈ ◡dom 𝐹 ↔ ∃𝑧⟨𝑦, 𝑥⟩𝐹𝑧)
21	12, 14, 20	3bitr4g 317	. . 3 ⊢ (Rel dom 𝐹 → (⟨𝑥, 𝑦⟩ ∈ dom tpos 𝐹 ↔ ⟨𝑥, 𝑦⟩ ∈ ◡dom 𝐹))
22	21	eqrelrdv2 5783	. 2 ⊢ (((Rel dom tpos 𝐹 ∧ Rel ◡dom 𝐹) ∧ Rel dom 𝐹) → dom tpos 𝐹 = ◡dom 𝐹)
23	8, 22	mpancom 700	1 ⊢ (Rel dom 𝐹 → dom tpos 𝐹 = ◡dom 𝐹)

Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 209   ∧ wa 400   = wceq 1570  ∃wex 1809   ∈ wcel 2143  Vcvv 3455   ⊆ wss 3906  ∅c0 4287  ⟨cop 4596   class class class wbr 5110   × cxp 5661  ^◡ccnv 5662  dom cdm 5663  Rel wrel 5668  tpos ctpos 8222

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1825  ax-4 1839  ax-5 1940  ax-6 1997  ax-7 2038  ax-8 2145  ax-9 2153  ax-10 2176  ax-11 2192  ax-12 2213  ax-ext 2735  ax-sep 5258  ax-nul 5270  ax-pow 5338  ax-pr 5406  ax-un 7734

This theorem depends on definitions:  df-bi 210  df-an 401  df-or 861  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1810  df-nf 1814  df-sb 2097  df-mo 2567  df-eu 2597  df-clab 2742  df-cleq 2755  df-clel 2838  df-nfc 2912  df-ne 2959  df-ral 3080  df-rex 3090  df-rab 3417  df-v 3457  df-dif 3909  df-un 3911  df-in 3913  df-ss 3923  df-nul 4288  df-if 4489  df-pw 4565  df-sn 4591  df-pr 4593  df-op 4597  df-uni 4874  df-br 5111  df-opab 5175  df-mpt 5194  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 6494  df-fun 6540  df-fn 6541  df-fv 6546  df-tpos 8223

This theorem is referenced by:  rntpos  8236  dftpos2  8240  dftpos3  8241  tposfn2  8245