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| Mirrors > Home > MPE Home > Th. List > recexsr | Structured version Visualization version GIF version | ||
| Description: The reciprocal of a nonzero signed real exists. Part of Proposition 9-4.3 of [Gleason] p. 126. (Contributed by NM, 15-May-1996.) (New usage is discouraged.) |
| Ref | Expression |
|---|---|
| recexsr | ⊢ ((𝐴 ∈ R ∧ 𝐴 ≠ 0R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sqgt0sr 11018 | . 2 ⊢ ((𝐴 ∈ R ∧ 𝐴 ≠ 0R) → 0R <R (𝐴 ·R 𝐴)) | |
| 2 | mulclsr 10996 | . . . . 5 ⊢ ((𝐴 ∈ R ∧ 𝑦 ∈ R) → (𝐴 ·R 𝑦) ∈ R) | |
| 3 | mulasssr 11002 | . . . . . . 7 ⊢ ((𝐴 ·R 𝐴) ·R 𝑦) = (𝐴 ·R (𝐴 ·R 𝑦)) | |
| 4 | 3 | eqeq1i 2742 | . . . . . 6 ⊢ (((𝐴 ·R 𝐴) ·R 𝑦) = 1R ↔ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R) |
| 5 | oveq2 7366 | . . . . . . . 8 ⊢ (𝑥 = (𝐴 ·R 𝑦) → (𝐴 ·R 𝑥) = (𝐴 ·R (𝐴 ·R 𝑦))) | |
| 6 | 5 | eqeq1d 2739 | . . . . . . 7 ⊢ (𝑥 = (𝐴 ·R 𝑦) → ((𝐴 ·R 𝑥) = 1R ↔ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R)) |
| 7 | 6 | rspcev 3565 | . . . . . 6 ⊢ (((𝐴 ·R 𝑦) ∈ R ∧ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
| 8 | 4, 7 | sylan2b 595 | . . . . 5 ⊢ (((𝐴 ·R 𝑦) ∈ R ∧ ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
| 9 | 2, 8 | sylan 581 | . . . 4 ⊢ (((𝐴 ∈ R ∧ 𝑦 ∈ R) ∧ ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
| 10 | 9 | rexlimdva2 3141 | . . 3 ⊢ (𝐴 ∈ R → (∃𝑦 ∈ R ((𝐴 ·R 𝐴) ·R 𝑦) = 1R → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R)) |
| 11 | recexsrlem 11015 | . . 3 ⊢ (0R <R (𝐴 ·R 𝐴) → ∃𝑦 ∈ R ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) | |
| 12 | 10, 11 | impel 505 | . 2 ⊢ ((𝐴 ∈ R ∧ 0R <R (𝐴 ·R 𝐴)) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
| 13 | 1, 12 | syldan 592 | 1 ⊢ ((𝐴 ∈ R ∧ 𝐴 ≠ 0R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
| Colors of variables: wff setvar class |
| Syntax hints: → wi 4 ∧ wa 395 = wceq 1542 ∈ wcel 2114 ≠ wne 2933 ∃wrex 3062 class class class wbr 5086 (class class class)co 7358 Rcnr 10777 0Rc0r 10778 1Rc1r 10779 ·R cmr 10782 <R cltr 10783 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1912 ax-6 1969 ax-7 2010 ax-8 2116 ax-9 2124 ax-10 2147 ax-11 2163 ax-12 2185 ax-ext 2709 ax-sep 5231 ax-nul 5241 ax-pow 5300 ax-pr 5368 ax-un 7680 ax-inf2 9551 |
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-3or 1088 df-3an 1089 df-tru 1545 df-fal 1555 df-ex 1782 df-nf 1786 df-sb 2069 df-mo 2540 df-eu 2570 df-clab 2716 df-cleq 2729 df-clel 2812 df-nfc 2886 df-ne 2934 df-ral 3053 df-rex 3063 df-rmo 3343 df-reu 3344 df-rab 3391 df-v 3432 df-sbc 3730 df-csb 3839 df-dif 3893 df-un 3895 df-in 3897 df-ss 3907 df-pss 3910 df-nul 4275 df-if 4468 df-pw 4544 df-sn 4569 df-pr 4571 df-op 4575 df-uni 4852 df-int 4891 df-iun 4936 df-br 5087 df-opab 5149 df-mpt 5168 df-tr 5194 df-id 5517 df-eprel 5522 df-po 5530 df-so 5531 df-fr 5575 df-we 5577 df-xp 5628 df-rel 5629 df-cnv 5630 df-co 5631 df-dm 5632 df-rn 5633 df-res 5634 df-ima 5635 df-pred 6257 df-ord 6318 df-on 6319 df-lim 6320 df-suc 6321 df-iota 6446 df-fun 6492 df-fn 6493 df-f 6494 df-f1 6495 df-fo 6496 df-f1o 6497 df-fv 6498 df-ov 7361 df-oprab 7362 df-mpo 7363 df-om 7809 df-1st 7933 df-2nd 7934 df-frecs 8222 df-wrecs 8253 df-recs 8302 df-rdg 8340 df-1o 8396 df-oadd 8400 df-omul 8401 df-er 8634 df-ec 8636 df-qs 8640 df-ni 10784 df-pli 10785 df-mi 10786 df-lti 10787 df-plpq 10820 df-mpq 10821 df-ltpq 10822 df-enq 10823 df-nq 10824 df-erq 10825 df-plq 10826 df-mq 10827 df-1nq 10828 df-rq 10829 df-ltnq 10830 df-np 10893 df-1p 10894 df-plp 10895 df-mp 10896 df-ltp 10897 df-enr 10967 df-nr 10968 df-plr 10969 df-mr 10970 df-ltr 10971 df-0r 10972 df-1r 10973 df-m1r 10974 |
| This theorem is referenced by: axrrecex 11075 |
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