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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 9927 | . 2 ⊢ ((𝐴 ∈ R ∧ 𝐴 ≠ 0R) → 0R <R (𝐴 ·R 𝐴)) | |
2 | recexsrlem 9924 | . . . 4 ⊢ (0R <R (𝐴 ·R 𝐴) → ∃𝑦 ∈ R ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) | |
3 | mulclsr 9905 | . . . . . . 7 ⊢ ((𝐴 ∈ R ∧ 𝑦 ∈ R) → (𝐴 ·R 𝑦) ∈ R) | |
4 | mulasssr 9911 | . . . . . . . . 9 ⊢ ((𝐴 ·R 𝐴) ·R 𝑦) = (𝐴 ·R (𝐴 ·R 𝑦)) | |
5 | 4 | eqeq1i 2627 | . . . . . . . 8 ⊢ (((𝐴 ·R 𝐴) ·R 𝑦) = 1R ↔ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R) |
6 | oveq2 6658 | . . . . . . . . . 10 ⊢ (𝑥 = (𝐴 ·R 𝑦) → (𝐴 ·R 𝑥) = (𝐴 ·R (𝐴 ·R 𝑦))) | |
7 | 6 | eqeq1d 2624 | . . . . . . . . 9 ⊢ (𝑥 = (𝐴 ·R 𝑦) → ((𝐴 ·R 𝑥) = 1R ↔ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R)) |
8 | 7 | rspcev 3309 | . . . . . . . 8 ⊢ (((𝐴 ·R 𝑦) ∈ R ∧ (𝐴 ·R (𝐴 ·R 𝑦)) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
9 | 5, 8 | sylan2b 492 | . . . . . . 7 ⊢ (((𝐴 ·R 𝑦) ∈ R ∧ ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
10 | 3, 9 | sylan 488 | . . . . . 6 ⊢ (((𝐴 ∈ R ∧ 𝑦 ∈ R) ∧ ((𝐴 ·R 𝐴) ·R 𝑦) = 1R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
11 | 10 | exp31 630 | . . . . 5 ⊢ (𝐴 ∈ R → (𝑦 ∈ R → (((𝐴 ·R 𝐴) ·R 𝑦) = 1R → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R))) |
12 | 11 | rexlimdv 3030 | . . . 4 ⊢ (𝐴 ∈ R → (∃𝑦 ∈ R ((𝐴 ·R 𝐴) ·R 𝑦) = 1R → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R)) |
13 | 2, 12 | syl5 34 | . . 3 ⊢ (𝐴 ∈ R → (0R <R (𝐴 ·R 𝐴) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R)) |
14 | 13 | imp 445 | . 2 ⊢ ((𝐴 ∈ R ∧ 0R <R (𝐴 ·R 𝐴)) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
15 | 1, 14 | syldan 487 | 1 ⊢ ((𝐴 ∈ R ∧ 𝐴 ≠ 0R) → ∃𝑥 ∈ R (𝐴 ·R 𝑥) = 1R) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 384 = wceq 1483 ∈ wcel 1990 ≠ wne 2794 ∃wrex 2913 class class class wbr 4653 (class class class)co 6650 Rcnr 9687 0Rc0r 9688 1Rc1r 9689 ·R cmr 9692 <R cltr 9693 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-8 1992 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-sep 4781 ax-nul 4789 ax-pow 4843 ax-pr 4906 ax-un 6949 ax-inf2 8538 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1038 df-3an 1039 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-eu 2474 df-mo 2475 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ne 2795 df-ral 2917 df-rex 2918 df-reu 2919 df-rmo 2920 df-rab 2921 df-v 3202 df-sbc 3436 df-csb 3534 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-pss 3590 df-nul 3916 df-if 4087 df-pw 4160 df-sn 4178 df-pr 4180 df-tp 4182 df-op 4184 df-uni 4437 df-int 4476 df-iun 4522 df-br 4654 df-opab 4713 df-mpt 4730 df-tr 4753 df-id 5024 df-eprel 5029 df-po 5035 df-so 5036 df-fr 5073 df-we 5075 df-xp 5120 df-rel 5121 df-cnv 5122 df-co 5123 df-dm 5124 df-rn 5125 df-res 5126 df-ima 5127 df-pred 5680 df-ord 5726 df-on 5727 df-lim 5728 df-suc 5729 df-iota 5851 df-fun 5890 df-fn 5891 df-f 5892 df-f1 5893 df-fo 5894 df-f1o 5895 df-fv 5896 df-ov 6653 df-oprab 6654 df-mpt2 6655 df-om 7066 df-1st 7168 df-2nd 7169 df-wrecs 7407 df-recs 7468 df-rdg 7506 df-1o 7560 df-oadd 7564 df-omul 7565 df-er 7742 df-ec 7744 df-qs 7748 df-ni 9694 df-pli 9695 df-mi 9696 df-lti 9697 df-plpq 9730 df-mpq 9731 df-ltpq 9732 df-enq 9733 df-nq 9734 df-erq 9735 df-plq 9736 df-mq 9737 df-1nq 9738 df-rq 9739 df-ltnq 9740 df-np 9803 df-1p 9804 df-plp 9805 df-mp 9806 df-ltp 9807 df-enr 9877 df-nr 9878 df-plr 9879 df-mr 9880 df-ltr 9881 df-0r 9882 df-1r 9883 df-m1r 9884 |
This theorem is referenced by: axrrecex 9984 |
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