Theorem connexd 5931

Description: The connectivity property. (Contributed by SF, 18-Mar-2015.)

Hypotheses

Ref	Expression
connexd.1	⊢ (φ → R Connex A)
connexd.2	⊢ (φ → X ∈ A)
connexd.3	⊢ (φ → Y ∈ A)

Assertion

Ref	Expression
connexd	⊢ (φ → (XRY ∨ YRX))

Proof of Theorem connexd

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

Step	Hyp	Ref	Expression
1		connexd.1	. 2 ⊢ (φ → R Connex A)
2		brex 4689	. . . . 5 ⊢ (R Connex A → (R ∈ V ∧ A ∈ V))
3		breq 4641	. . . . . . . 8 ⊢ (r = R → (xry ↔ xRy))
4		breq 4641	. . . . . . . 8 ⊢ (r = R → (yrx ↔ yRx))
5	3, 4	orbi12d 690	. . . . . . 7 ⊢ (r = R → ((xry ∨ yrx) ↔ (xRy ∨ yRx)))
6	5	2ralbidv 2656	. . . . . 6 ⊢ (r = R → (∀x ∈ a ∀y ∈ a (xry ∨ yrx) ↔ ∀x ∈ a ∀y ∈ a (xRy ∨ yRx)))
7		raleq 2807	. . . . . . 7 ⊢ (a = A → (∀y ∈ a (xRy ∨ yRx) ↔ ∀y ∈ A (xRy ∨ yRx)))
8	7	raleqbi1dv 2815	. . . . . 6 ⊢ (a = A → (∀x ∈ a ∀y ∈ a (xRy ∨ yRx) ↔ ∀x ∈ A ∀y ∈ A (xRy ∨ yRx)))
9		df-connex 5903	. . . . . 6 ⊢ Connex = {⟨r, a⟩ ∣ ∀x ∈ a ∀y ∈ a (xry ∨ yrx)}
10	6, 8, 9	brabg 4706	. . . . 5 ⊢ ((R ∈ V ∧ A ∈ V) → (R Connex A ↔ ∀x ∈ A ∀y ∈ A (xRy ∨ yRx)))
11	2, 10	syl 15	. . . 4 ⊢ (R Connex A → (R Connex A ↔ ∀x ∈ A ∀y ∈ A (xRy ∨ yRx)))
12	11	ibi 232	. . 3 ⊢ (R Connex A → ∀x ∈ A ∀y ∈ A (xRy ∨ yRx))
13		connexd.2	. . . 4 ⊢ (φ → X ∈ A)
14		connexd.3	. . . 4 ⊢ (φ → Y ∈ A)
15		breq1 4642	. . . . . 6 ⊢ (x = X → (xRy ↔ XRy))
16		breq2 4643	. . . . . 6 ⊢ (x = X → (yRx ↔ yRX))
17	15, 16	orbi12d 690	. . . . 5 ⊢ (x = X → ((xRy ∨ yRx) ↔ (XRy ∨ yRX)))
18		breq2 4643	. . . . . 6 ⊢ (y = Y → (XRy ↔ XRY))
19		breq1 4642	. . . . . 6 ⊢ (y = Y → (yRX ↔ YRX))
20	18, 19	orbi12d 690	. . . . 5 ⊢ (y = Y → ((XRy ∨ yRX) ↔ (XRY ∨ YRX)))
21	17, 20	rspc2v 2961	. . . 4 ⊢ ((X ∈ A ∧ Y ∈ A) → (∀x ∈ A ∀y ∈ A (xRy ∨ yRx) → (XRY ∨ YRX)))
22	13, 14, 21	syl2anc 642	. . 3 ⊢ (φ → (∀x ∈ A ∀y ∈ A (xRy ∨ yRx) → (XRY ∨ YRX)))
23	12, 22	syl5 28	. 2 ⊢ (φ → (R Connex A → (XRY ∨ YRX)))
24	1, 23	mpd 14	1 ⊢ (φ → (XRY ∨ YRX))

Syntax hints:   → wi 4   ↔ wb 176   ∨ wo 357   ∧ wa 358   = wceq 1642   ∈ wcel 1710  ∀wral 2614  Vcvv 2859   class class class wbr 4639   Connex cconnex 5892

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-13 1712  ax-14 1714  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334  ax-nin 4078  ax-xp 4079  ax-cnv 4080  ax-1c 4081  ax-sset 4082  ax-si 4083  ax-ins2 4084  ax-ins3 4085  ax-typlower 4086  ax-sn 4087

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-eu 2208  df-mo 2209  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-ne 2518  df-ral 2619  df-rex 2620  df-reu 2621  df-rmo 2622  df-rab 2623  df-v 2861  df-sbc 3047  df-nin 3211  df-compl 3212  df-in 3213  df-un 3214  df-dif 3215  df-symdif 3216  df-ss 3259  df-pss 3261  df-nul 3551  df-if 3663  df-pw 3724  df-sn 3741  df-pr 3742  df-uni 3892  df-int 3927  df-opk 4058  df-1c 4136  df-pw1 4137  df-uni1 4138  df-xpk 4185  df-cnvk 4186  df-ins2k 4187  df-ins3k 4188  df-imak 4189  df-cok 4190  df-p6 4191  df-sik 4192  df-ssetk 4193  df-imagek 4194  df-idk 4195  df-iota 4339  df-0c 4377  df-addc 4378  df-nnc 4379  df-fin 4380  df-lefin 4440  df-ltfin 4441  df-ncfin 4442  df-tfin 4443  df-evenfin 4444  df-oddfin 4445  df-sfin 4446  df-spfin 4447  df-phi 4565  df-op 4566  df-proj1 4567  df-proj2 4568  df-opab 4623  df-br 4640  df-connex 5903

This theorem is referenced by:  weds  5938  nchoicelem8  6296