Theorem kardex 9583

Description: The collection of all sets equinumerous to a set 𝐴 and having the least possible rank is a set. This is the part of the justification of the definition of kard of [Enderton] p. 222. (Contributed by NM, 14-Dec-2003.)

Assertion

Ref	Expression
kardex	⊢ {𝑥 ∣ (𝑥 ≈ 𝐴 ∧ ∀𝑦(𝑦 ≈ 𝐴 → (rank‘𝑥) ⊆ (rank‘𝑦)))} ∈ V

Distinct variable group:   𝑥,𝑦,𝐴

Proof of Theorem kardex

Dummy variable 𝑧 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-rab 3072	. . 3 ⊢ {𝑥 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} ∣ ∀𝑦 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} (rank‘𝑥) ⊆ (rank‘𝑦)} = {𝑥 ∣ (𝑥 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} ∧ ∀𝑦 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} (rank‘𝑥) ⊆ (rank‘𝑦))}
2		vex 3426	. . . . . 6 ⊢ 𝑥 ∈ V
3		breq1 5073	. . . . . 6 ⊢ (𝑧 = 𝑥 → (𝑧 ≈ 𝐴 ↔ 𝑥 ≈ 𝐴))
4	2, 3	elab 3602	. . . . 5 ⊢ (𝑥 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} ↔ 𝑥 ≈ 𝐴)
5		breq1 5073	. . . . . 6 ⊢ (𝑧 = 𝑦 → (𝑧 ≈ 𝐴 ↔ 𝑦 ≈ 𝐴))
6	5	ralab 3621	. . . . 5 ⊢ (∀𝑦 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} (rank‘𝑥) ⊆ (rank‘𝑦) ↔ ∀𝑦(𝑦 ≈ 𝐴 → (rank‘𝑥) ⊆ (rank‘𝑦)))
7	4, 6	anbi12i 626	. . . 4 ⊢ ((𝑥 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} ∧ ∀𝑦 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} (rank‘𝑥) ⊆ (rank‘𝑦)) ↔ (𝑥 ≈ 𝐴 ∧ ∀𝑦(𝑦 ≈ 𝐴 → (rank‘𝑥) ⊆ (rank‘𝑦))))
8	7	abbii 2809	. . 3 ⊢ {𝑥 ∣ (𝑥 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} ∧ ∀𝑦 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} (rank‘𝑥) ⊆ (rank‘𝑦))} = {𝑥 ∣ (𝑥 ≈ 𝐴 ∧ ∀𝑦(𝑦 ≈ 𝐴 → (rank‘𝑥) ⊆ (rank‘𝑦)))}
9	1, 8	eqtri 2766	. 2 ⊢ {𝑥 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} ∣ ∀𝑦 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} (rank‘𝑥) ⊆ (rank‘𝑦)} = {𝑥 ∣ (𝑥 ≈ 𝐴 ∧ ∀𝑦(𝑦 ≈ 𝐴 → (rank‘𝑥) ⊆ (rank‘𝑦)))}
10		scottex 9574	. 2 ⊢ {𝑥 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} ∣ ∀𝑦 ∈ {𝑧 ∣ 𝑧 ≈ 𝐴} (rank‘𝑥) ⊆ (rank‘𝑦)} ∈ V
11	9, 10	eqeltrri 2836	1 ⊢ {𝑥 ∣ (𝑥 ≈ 𝐴 ∧ ∀𝑦(𝑦 ≈ 𝐴 → (rank‘𝑥) ⊆ (rank‘𝑦)))} ∈ V

Syntax hints:   → wi 4   ∧ wa 395  ∀wal 1537   ∈ wcel 2108  {cab 2715  ∀wral 3063  {crab 3067  Vcvv 3422   ⊆ wss 3883   class class class wbr 5070  ‘cfv 6418   ≈ cen 8688  rankcrnk 9452

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1799  ax-4 1813  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2110  ax-9 2118  ax-10 2139  ax-11 2156  ax-12 2173  ax-ext 2709  ax-rep 5205  ax-sep 5218  ax-nul 5225  ax-pow 5283  ax-pr 5347  ax-un 7566  ax-reg 9281  ax-inf2 9329

This theorem depends on definitions:  df-bi 206  df-an 396  df-or 844  df-3or 1086  df-3an 1087  df-tru 1542  df-fal 1552  df-ex 1784  df-nf 1788  df-sb 2069  df-mo 2540  df-eu 2569  df-clab 2716  df-cleq 2730  df-clel 2817  df-nfc 2888  df-ne 2943  df-ral 3068  df-rex 3069  df-reu 3070  df-rab 3072  df-v 3424  df-sbc 3712  df-csb 3829  df-dif 3886  df-un 3888  df-in 3890  df-ss 3900  df-pss 3902  df-nul 4254  df-if 4457  df-pw 4532  df-sn 4559  df-pr 4561  df-tp 4563  df-op 4565  df-uni 4837  df-int 4877  df-iun 4923  df-br 5071  df-opab 5133  df-mpt 5154  df-tr 5188  df-id 5480  df-eprel 5486  df-po 5494  df-so 5495  df-fr 5535  df-we 5537  df-xp 5586  df-rel 5587  df-cnv 5588  df-co 5589  df-dm 5590  df-rn 5591  df-res 5592  df-ima 5593  df-pred 6191  df-ord 6254  df-on 6255  df-lim 6256  df-suc 6257  df-iota 6376  df-fun 6420  df-fn 6421  df-f 6422  df-f1 6423  df-fo 6424  df-f1o 6425  df-fv 6426  df-ov 7258  df-om 7688  df-2nd 7805  df-frecs 8068  df-wrecs 8099  df-recs 8173  df-rdg 8212  df-r1 9453  df-rank 9454

This theorem is referenced by: (None)