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Theorem prnmax 10893

Description: A positive real has no largest member. Definition 9-3.1(iii) of [Gleason] p. 121. (Contributed by NM, 9-Mar-1996.) (Revised by Mario Carneiro, 11-May-2013.) (New usage is discouraged.)

**Assertion**
Ref	Expression
prnmax	⊢ ((𝐴 ∈ P ∧ 𝐵 ∈ 𝐴) → ∃𝑥 ∈ 𝐴 𝐵 <_Q 𝑥)

Distinct variable groups: 𝑥,𝐴 𝑥,𝐵

Proof of Theorem prnmax Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		eleq1 2821	. . . . 5 ⊢ (𝑦 = 𝐵 → (𝑦 ∈ 𝐴 ↔ 𝐵 ∈ 𝐴))
2	1	anbi2d 630	. . . 4 ⊢ (𝑦 = 𝐵 → ((𝐴 ∈ P ∧ 𝑦 ∈ 𝐴) ↔ (𝐴 ∈ P ∧ 𝐵 ∈ 𝐴)))
3		breq1 5096	. . . . 5 ⊢ (𝑦 = 𝐵 → (𝑦 <_Q 𝑥 ↔ 𝐵 <_Q 𝑥))
4	3	rexbidv 3157	. . . 4 ⊢ (𝑦 = 𝐵 → (∃𝑥 ∈ 𝐴 𝑦 <_Q 𝑥 ↔ ∃𝑥 ∈ 𝐴 𝐵 <_Q 𝑥))
5	2, 4	imbi12d 344	. . 3 ⊢ (𝑦 = 𝐵 → (((𝐴 ∈ P ∧ 𝑦 ∈ 𝐴) → ∃𝑥 ∈ 𝐴 𝑦 <_Q 𝑥) ↔ ((𝐴 ∈ P ∧ 𝐵 ∈ 𝐴) → ∃𝑥 ∈ 𝐴 𝐵 <_Q 𝑥)))
6		elnpi 10886	. . . . . 6 ⊢ (𝐴 ∈ P ↔ ((𝐴 ∈ V ∧ ∅ ⊊ 𝐴 ∧ 𝐴 ⊊ Q) ∧ ∀𝑦 ∈ 𝐴 (∀𝑥(𝑥 <_Q 𝑦 → 𝑥 ∈ 𝐴) ∧ ∃𝑥 ∈ 𝐴 𝑦 <_Q 𝑥)))
7	6	simprbi 496	. . . . 5 ⊢ (𝐴 ∈ P → ∀𝑦 ∈ 𝐴 (∀𝑥(𝑥 <_Q 𝑦 → 𝑥 ∈ 𝐴) ∧ ∃𝑥 ∈ 𝐴 𝑦 <_Q 𝑥))
8	7	r19.21bi 3225	. . . 4 ⊢ ((𝐴 ∈ P ∧ 𝑦 ∈ 𝐴) → (∀𝑥(𝑥 <_Q 𝑦 → 𝑥 ∈ 𝐴) ∧ ∃𝑥 ∈ 𝐴 𝑦 <_Q 𝑥))
9	8	simprd 495	. . 3 ⊢ ((𝐴 ∈ P ∧ 𝑦 ∈ 𝐴) → ∃𝑥 ∈ 𝐴 𝑦 <_Q 𝑥)
10	5, 9	vtoclg 3508	. 2 ⊢ (𝐵 ∈ 𝐴 → ((𝐴 ∈ P ∧ 𝐵 ∈ 𝐴) → ∃𝑥 ∈ 𝐴 𝐵 <_Q 𝑥))
11	10	anabsi7 671	1 ⊢ ((𝐴 ∈ P ∧ 𝐵 ∈ 𝐴) → ∃𝑥 ∈ 𝐴 𝐵 <_Q 𝑥)

Colors of variables: wff setvar class

Syntax hints: → wi 4 ∧ wa 395 ∧ w3a 1086 ∀wal 1539 = wceq 1541 ∈ wcel 2113 ∀wral 3048 ∃wrex 3057 Vcvv 3437 ⊊ wpss 3899 ∅c0 4282 class class class wbr 5093 Qcnq 10750 <_Q cltq 10756 Pcnp 10757

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1968 ax-7 2009 ax-8 2115 ax-9 2123 ax-12 2182 ax-ext 2705

This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3an 1088 df-tru 1544 df-fal 1554 df-ex 1781 df-sb 2068 df-clab 2712 df-cleq 2725 df-clel 2808 df-ne 2930 df-ral 3049 df-rex 3058 df-rab 3397 df-v 3439 df-dif 3901 df-un 3903 df-ss 3915 df-pss 3918 df-nul 4283 df-if 4475 df-sn 4576 df-pr 4578 df-op 4582 df-br 5094 df-np 10879

This theorem is referenced by: npomex 10894 prnmadd 10895 genpnmax 10905 1idpr 10927 ltexprlem4 10937 reclem3pr 10947 suplem1pr 10950

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