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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 10606 | . 2 ⊢ ((𝐴 ∈ R ∧ 𝐴 ≠ 0R) → 0R <R (𝐴 ·R 𝐴)) | |
2 | mulclsr 10584 | . . . . 5 ⊢ ((𝐴 ∈ R ∧ 𝑦 ∈ R) → (𝐴 ·R 𝑦) ∈ R) | |
3 | mulasssr 10590 | . . . . . . 7 ⊢ ((𝐴 ·R 𝐴) ·R 𝑦) = (𝐴 ·R (𝐴 ·R 𝑦)) | |
4 | 3 | eqeq1i 2743 | . . . . . 6 ⊢ (((𝐴 ·R 𝐴) ·R 𝑦) = 1R ↔ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R) |
5 | oveq2 7178 | . . . . . . . 8 ⊢ (𝑥 = (𝐴 ·R 𝑦) → (𝐴 ·R 𝑥) = (𝐴 ·R (𝐴 ·R 𝑦))) | |
6 | 5 | eqeq1d 2740 | . . . . . . 7 ⊢ (𝑥 = (𝐴 ·R 𝑦) → ((𝐴 ·R 𝑥) = 1R ↔ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R)) |
7 | 6 | rspcev 3526 | . . . . . 6 ⊢ (((𝐴 ·R 𝑦) ∈ R ∧ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
8 | 4, 7 | sylan2b 597 | . . . . 5 ⊢ (((𝐴 ·R 𝑦) ∈ R ∧ ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
9 | 2, 8 | sylan 583 | . . . 4 ⊢ (((𝐴 ∈ R ∧ 𝑦 ∈ R) ∧ ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
10 | 9 | rexlimdva2 3197 | . . 3 ⊢ (𝐴 ∈ R → (∃𝑦 ∈ R ((𝐴 ·R 𝐴) ·R 𝑦) = 1R → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R)) |
11 | recexsrlem 10603 | . . 3 ⊢ (0R <R (𝐴 ·R 𝐴) → ∃𝑦 ∈ R ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) | |
12 | 10, 11 | impel 509 | . 2 ⊢ ((𝐴 ∈ R ∧ 0R <R (𝐴 ·R 𝐴)) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
13 | 1, 12 | syldan 594 | 1 ⊢ ((𝐴 ∈ R ∧ 𝐴 ≠ 0R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 399 = wceq 1542 ∈ wcel 2114 ≠ wne 2934 ∃wrex 3054 class class class wbr 5030 (class class class)co 7170 Rcnr 10365 0Rc0r 10366 1Rc1r 10367 ·R cmr 10370 <R cltr 10371 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1802 ax-4 1816 ax-5 1917 ax-6 1975 ax-7 2020 ax-8 2116 ax-9 2124 ax-10 2145 ax-11 2162 ax-12 2179 ax-ext 2710 ax-sep 5167 ax-nul 5174 ax-pow 5232 ax-pr 5296 ax-un 7479 ax-inf2 9177 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 847 df-3or 1089 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1787 df-nf 1791 df-sb 2075 df-mo 2540 df-eu 2570 df-clab 2717 df-cleq 2730 df-clel 2811 df-nfc 2881 df-ne 2935 df-ral 3058 df-rex 3059 df-reu 3060 df-rmo 3061 df-rab 3062 df-v 3400 df-sbc 3681 df-csb 3791 df-dif 3846 df-un 3848 df-in 3850 df-ss 3860 df-pss 3862 df-nul 4212 df-if 4415 df-pw 4490 df-sn 4517 df-pr 4519 df-tp 4521 df-op 4523 df-uni 4797 df-int 4837 df-iun 4883 df-br 5031 df-opab 5093 df-mpt 5111 df-tr 5137 df-id 5429 df-eprel 5434 df-po 5442 df-so 5443 df-fr 5483 df-we 5485 df-xp 5531 df-rel 5532 df-cnv 5533 df-co 5534 df-dm 5535 df-rn 5536 df-res 5537 df-ima 5538 df-pred 6129 df-ord 6175 df-on 6176 df-lim 6177 df-suc 6178 df-iota 6297 df-fun 6341 df-fn 6342 df-f 6343 df-f1 6344 df-fo 6345 df-f1o 6346 df-fv 6347 df-ov 7173 df-oprab 7174 df-mpo 7175 df-om 7600 df-1st 7714 df-2nd 7715 df-wrecs 7976 df-recs 8037 df-rdg 8075 df-1o 8131 df-oadd 8135 df-omul 8136 df-er 8320 df-ec 8322 df-qs 8326 df-ni 10372 df-pli 10373 df-mi 10374 df-lti 10375 df-plpq 10408 df-mpq 10409 df-ltpq 10410 df-enq 10411 df-nq 10412 df-erq 10413 df-plq 10414 df-mq 10415 df-1nq 10416 df-rq 10417 df-ltnq 10418 df-np 10481 df-1p 10482 df-plp 10483 df-mp 10484 df-ltp 10485 df-enr 10555 df-nr 10556 df-plr 10557 df-mr 10558 df-ltr 10559 df-0r 10560 df-1r 10561 df-m1r 10562 |
This theorem is referenced by: axrrecex 10663 |
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