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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 1979). 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 3061 | . . . 4 ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑)) | |
2 | exintr 1894 | . . . 4 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → 𝜑) → (∃𝑥 𝑥 ∈ 𝐴 → ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑))) | |
3 | 1, 2 | sylbi 216 | . . 3 ⊢ (∀𝑥 ∈ 𝐴 𝜑 → (∃𝑥 𝑥 ∈ 𝐴 → ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑))) |
4 | n0 4346 | . . 3 ⊢ (𝐴 ≠ ∅ ↔ ∃𝑥 𝑥 ∈ 𝐴) | |
5 | df-rex 3070 | . . 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 1538 ∃wex 1780 ∈ wcel 2105 ≠ wne 2939 ∀wral 3060 ∃wrex 3069 ∅c0 4322 |
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 1912 ax-6 1970 ax-7 2010 ax-9 2115 ax-ext 2702 |
This theorem depends on definitions: df-bi 206 df-an 396 df-tru 1543 df-fal 1553 df-ex 1781 df-sb 2067 df-clab 2709 df-cleq 2723 df-ne 2940 df-ral 3061 df-rex 3070 df-dif 3951 df-nul 4323 |
This theorem is referenced by: r19.2zb 4495 intssuni 4974 iinssiun 5010 riinn0 5086 iinexg 5341 reusv2lem2 5397 reusv2lem3 5398 xpiindi 5835 cnviin 6285 eusvobj2 7404 iiner 8789 finsschain 9365 cfeq0 10257 cfsuc 10258 iundom2g 10541 alephval2 10573 prlem934 11034 supaddc 12188 supadd 12189 supmul1 12190 supmullem2 12192 supmul 12193 rexfiuz 15301 r19.2uz 15305 climuni 15503 caurcvg 15630 caurcvg2 15631 caucvg 15632 pc2dvds 16819 vdwmc2 16919 vdwlem6 16926 vdwnnlem3 16937 issubg4 19068 gexcl3 19503 lbsextlem2 21006 iincld 22863 opnnei 22944 cncnp2 23105 lmmo 23204 iunconn 23252 ptbasfi 23405 filuni 23709 isfcls 23833 fclsopn 23838 ustfilxp 24037 nrginvrcn 24529 lebnumlem3 24809 cfil3i 25117 caun0 25129 iscmet3 25141 nulmbl2 25385 dyadmax 25447 itg2seq 25592 itg2monolem1 25600 bddiblnc 25691 rolle 25842 c1lip1 25850 taylfval 26210 ulm0 26242 frgrreg 30080 bnj906 34405 cvmliftlem15 34753 dfon2lem6 35230 filnetlem4 35730 itg2addnclem 37003 itg2addnc 37006 itg2gt0cn 37007 ftc1anc 37033 filbcmb 37072 incsequz 37080 isbnd2 37115 isbnd3 37116 ssbnd 37120 unichnidl 37363 iunconnlem2 44159 upbdrech 44474 infxrpnf 44615 |
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