Theorem ax6e2eq 44528

Description: Alternate form of ax6e 2391 for non-distinct 𝑥, 𝑦 and 𝑢 = 𝑣. ax6e2eq 44528 is derived from ax6e2eqVD 44878. (Contributed by Alan Sare, 25-Mar-2014.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
ax6e2eq	⊢ (∀𝑥 𝑥 = 𝑦 → (𝑢 = 𝑣 → ∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣)))

Distinct variable groups:   𝑥,𝑢   𝑦,𝑢   𝑥,𝑣   𝑦,𝑣

Proof of Theorem ax6e2eq

Step	Hyp	Ref	Expression
1		ax6ev 1969	. . . . . . 7 ⊢ ∃𝑥 𝑥 = 𝑢
2		hbae 2439	. . . . . . . 8 ⊢ (∀𝑥 𝑥 = 𝑦 → ∀𝑥∀𝑥 𝑥 = 𝑦)
3		ax7 2015	. . . . . . . . . 10 ⊢ (𝑥 = 𝑦 → (𝑥 = 𝑢 → 𝑦 = 𝑢))
4	3	sps 2186	. . . . . . . . 9 ⊢ (∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑢 → 𝑦 = 𝑢))
5	4	ancld 550	. . . . . . . 8 ⊢ (∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑢 → (𝑥 = 𝑢 ∧ 𝑦 = 𝑢)))
6	2, 5	eximdh 1863	. . . . . . 7 ⊢ (∀𝑥 𝑥 = 𝑦 → (∃𝑥 𝑥 = 𝑢 → ∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢)))
7	1, 6	mpi 20	. . . . . 6 ⊢ (∀𝑥 𝑥 = 𝑦 → ∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢))
8	7	axc4i 2326	. . . . 5 ⊢ (∀𝑥 𝑥 = 𝑦 → ∀𝑥∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢))
9		axc11 2438	. . . . 5 ⊢ (∀𝑥 𝑥 = 𝑦 → (∀𝑥∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢) → ∀𝑦∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢)))
10	8, 9	mpd 15	. . . 4 ⊢ (∀𝑥 𝑥 = 𝑦 → ∀𝑦∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢))
11		19.2 1976	. . . 4 ⊢ (∀𝑦∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢) → ∃𝑦∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢))
12	10, 11	syl 17	. . 3 ⊢ (∀𝑥 𝑥 = 𝑦 → ∃𝑦∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢))
13		excomim 2164	. . 3 ⊢ (∃𝑦∃𝑥(𝑥 = 𝑢 ∧ 𝑦 = 𝑢) → ∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑢))
14	12, 13	syl 17	. 2 ⊢ (∀𝑥 𝑥 = 𝑦 → ∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑢))
15		equtrr 2021	. . . 4 ⊢ (𝑢 = 𝑣 → (𝑦 = 𝑢 → 𝑦 = 𝑣))
16	15	anim2d 611	. . 3 ⊢ (𝑢 = 𝑣 → ((𝑥 = 𝑢 ∧ 𝑦 = 𝑢) → (𝑥 = 𝑢 ∧ 𝑦 = 𝑣)))
17	16	2eximdv 1918	. 2 ⊢ (𝑢 = 𝑣 → (∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑢) → ∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣)))
18	14, 17	syl5com 31	1 ⊢ (∀𝑥 𝑥 = 𝑦 → (𝑢 = 𝑣 → ∃𝑥∃𝑦(𝑥 = 𝑢 ∧ 𝑦 = 𝑣)))

Syntax hints:   → wi 4   ∧ wa 395  ∀wal 1535  ∃wex 1777

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1793  ax-4 1807  ax-5 1909  ax-6 1967  ax-7 2007  ax-10 2141  ax-11 2158  ax-12 2178  ax-13 2380

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 847  df-tru 1540  df-ex 1778  df-nf 1782

This theorem is referenced by:  ax6e2ndeq  44530  ax6e2ndeqVD  44880  ax6e2ndeqALT  44902