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Mirrors > Home > MPE Home > Th. List > r19.2z | Structured version Visualization version GIF version |
Description: Theorem 19.2 of [Margaris] p. 89 with restricted quantifiers (compare 19.2 1973). The restricted version is valid only when the domain of quantification is not empty. (Contributed by NM, 15-Nov-2003.) |
Ref | Expression |
---|---|
r19.2z | ⊢ ((𝐴 ≠ ∅ ∧ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑥 ∈ 𝐴 𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-ral 3059 | . . . 4 ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑)) | |
2 | exintr 1889 | . . . 4 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → 𝜑) → (∃𝑥 𝑥 ∈ 𝐴 → ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑))) | |
3 | 1, 2 | sylbi 217 | . . 3 ⊢ (∀𝑥 ∈ 𝐴 𝜑 → (∃𝑥 𝑥 ∈ 𝐴 → ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑))) |
4 | n0 4358 | . . 3 ⊢ (𝐴 ≠ ∅ ↔ ∃𝑥 𝑥 ∈ 𝐴) | |
5 | df-rex 3068 | . . 3 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
6 | 3, 4, 5 | 3imtr4g 296 | . 2 ⊢ (∀𝑥 ∈ 𝐴 𝜑 → (𝐴 ≠ ∅ → ∃𝑥 ∈ 𝐴 𝜑)) |
7 | 6 | impcom 407 | 1 ⊢ ((𝐴 ≠ ∅ ∧ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑥 ∈ 𝐴 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 ∀wal 1534 ∃wex 1775 ∈ wcel 2105 ≠ wne 2937 ∀wral 3058 ∃wrex 3067 ∅c0 4338 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1791 ax-4 1805 ax-5 1907 ax-6 1964 ax-7 2004 ax-9 2115 ax-ext 2705 |
This theorem depends on definitions: df-bi 207 df-an 396 df-tru 1539 df-fal 1549 df-ex 1776 df-sb 2062 df-clab 2712 df-cleq 2726 df-ne 2938 df-ral 3059 df-rex 3068 df-dif 3965 df-nul 4339 |
This theorem is referenced by: r19.2zb 4501 intssuni 4974 iinssiun 5009 riinn0 5087 iinexg 5353 reusv2lem2 5404 reusv2lem3 5405 xpiindi 5848 cnviin 6307 eusvobj2 7422 iiner 8827 finsschain 9396 cfeq0 10293 cfsuc 10294 iundom2g 10577 alephval2 10609 prlem934 11070 supaddc 12232 supadd 12233 supmul1 12234 supmullem2 12236 supmul 12237 rexfiuz 15382 r19.2uz 15386 climuni 15584 caurcvg 15709 caurcvg2 15710 caucvg 15711 pc2dvds 16912 vdwmc2 17012 vdwlem6 17019 vdwnnlem3 17030 issubg4 19175 gexcl3 19619 lbsextlem2 21178 iincld 23062 opnnei 23143 cncnp2 23304 lmmo 23403 iunconn 23451 ptbasfi 23604 filuni 23908 isfcls 24032 fclsopn 24037 ustfilxp 24236 nrginvrcn 24728 lebnumlem3 25008 cfil3i 25316 caun0 25328 iscmet3 25340 nulmbl2 25584 dyadmax 25646 itg2seq 25791 itg2monolem1 25799 bddiblnc 25891 rolle 26042 c1lip1 26050 taylfval 26414 ulm0 26448 frgrreg 30422 bnj906 34922 cvmliftlem15 35282 dfon2lem6 35769 filnetlem4 36363 itg2addnclem 37657 itg2addnc 37660 itg2gt0cn 37661 ftc1anc 37687 filbcmb 37726 incsequz 37734 isbnd2 37769 isbnd3 37770 ssbnd 37774 unichnidl 38017 iunconnlem2 44932 upbdrech 45255 infxrpnf 45395 |
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