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Theorem infpssALT 10270

Description: Alternate proof of infpss 10172, shorter but requiring Replacement (ax-rep 5227). (Contributed by Stefan O'Rear, 30-Oct-2014.) (Revised by Mario Carneiro, 16-May-2015.) (Proof modification is discouraged.) (New usage is discouraged.)

**Assertion**
Ref	Expression
infpssALT	⊢ (ω ≼ 𝐴 → ∃𝑥(𝑥 ⊊ 𝐴 ∧ 𝑥 ≈ 𝐴))

Distinct variable group: 𝑥,𝐴

**Proof of Theorem infpssALT**
Step	Hyp	Ref	Expression
1		ominf4 10269	. 2 ⊢ ¬ ω ∈ Fin^IV
2		reldom 8933	. . . . 5 ⊢ Rel ≼
3	2	brrelex2i 5704	. . . 4 ⊢ (ω ≼ 𝐴 → 𝐴 ∈ V)
4		isfin4 10254	. . . 4 ⊢ (𝐴 ∈ V → (𝐴 ∈ Fin^IV ↔ ¬ ∃𝑥(𝑥 ⊊ 𝐴 ∧ 𝑥 ≈ 𝐴)))
5	3, 4	syl 17	. . 3 ⊢ (ω ≼ 𝐴 → (𝐴 ∈ Fin^IV ↔ ¬ ∃𝑥(𝑥 ⊊ 𝐴 ∧ 𝑥 ≈ 𝐴)))
6		domfin4 10268	. . . 4 ⊢ ((𝐴 ∈ Fin^IV ∧ ω ≼ 𝐴) → ω ∈ Fin^IV)
7	6	expcom 417	. . 3 ⊢ (ω ≼ 𝐴 → (𝐴 ∈ Fin^IV → ω ∈ Fin^IV))
8	5, 7	sylbird 262	. 2 ⊢ (ω ≼ 𝐴 → (¬ ∃𝑥(𝑥 ⊊ 𝐴 ∧ 𝑥 ≈ 𝐴) → ω ∈ Fin^IV))
9	1, 8	mt3i 149	1 ⊢ (ω ≼ 𝐴 → ∃𝑥(𝑥 ⊊ 𝐴 ∧ 𝑥 ≈ 𝐴))

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 208 ∧ wa 399 ∃wex 1799 ∈ wcel 2142 Vcvv 3454 ⊊ wpss 3905 class class class wbr 5100 ωcom 7846 ≈ cen 8924 ≼ cdom 8925 Fin^IVcfin4 10237

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1815 ax-4 1829 ax-5 1930 ax-6 1987 ax-7 2028 ax-8 2144 ax-9 2152 ax-10 2175 ax-11 2191 ax-12 2212 ax-ext 2734 ax-rep 5227 ax-sep 5246 ax-nul 5256 ax-pow 5322 ax-pr 5390 ax-un 7718

This theorem depends on definitions: df-bi 209 df-an 400 df-or 859 df-3or 1099 df-3an 1100 df-tru 1563 df-fal 1573 df-ex 1800 df-nf 1804 df-sb 2091 df-mo 2566 df-eu 2596 df-clab 2741 df-cleq 2754 df-clel 2837 df-nfc 2911 df-ne 2958 df-ral 3077 df-rex 3087 df-reu 3368 df-rab 3415 df-v 3456 df-sbc 3745 df-csb 3853 df-dif 3907 df-un 3909 df-in 3911 df-ss 3921 df-pss 3924 df-nul 4286 df-if 4481 df-pw 4557 df-sn 4583 df-pr 4585 df-op 4589 df-uni 4866 df-iun 4951 df-br 5101 df-opab 5163 df-mpt 5182 df-tr 5208 df-id 5542 df-eprel 5547 df-po 5555 df-so 5556 df-fr 5600 df-we 5602 df-xp 5653 df-rel 5654 df-cnv 5655 df-co 5656 df-dm 5657 df-rn 5658 df-res 5659 df-ima 5660 df-ord 6349 df-on 6350 df-lim 6351 df-suc 6352 df-iota 6477 df-fun 6523 df-fn 6524 df-f 6525 df-f1 6526 df-fo 6527 df-f1o 6528 df-fv 6529 df-om 7847 df-er 8678 df-en 8928 df-dom 8929 df-fin4 10244

This theorem is referenced by: (None)

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