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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 1978). 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 3060 | . . . 4 ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑)) | |
2 | exintr 1893 | . . . 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 4345 | . . 3 ⊢ (𝐴 ≠ ∅ ↔ ∃𝑥 𝑥 ∈ 𝐴) | |
5 | df-rex 3069 | . . 3 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
6 | 3, 4, 5 | 3imtr4g 295 | . 2 ⊢ (∀𝑥 ∈ 𝐴 𝜑 → (𝐴 ≠ ∅ → ∃𝑥 ∈ 𝐴 𝜑)) |
7 | 6 | impcom 406 | 1 ⊢ ((𝐴 ≠ ∅ ∧ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑥 ∈ 𝐴 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 394 ∀wal 1537 ∃wex 1779 ∈ wcel 2104 ≠ wne 2938 ∀wral 3059 ∃wrex 3068 ∅c0 4321 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1911 ax-6 1969 ax-7 2009 ax-9 2114 ax-ext 2701 |
This theorem depends on definitions: df-bi 206 df-an 395 df-tru 1542 df-fal 1552 df-ex 1780 df-sb 2066 df-clab 2708 df-cleq 2722 df-ne 2939 df-ral 3060 df-rex 3069 df-dif 3950 df-nul 4322 |
This theorem is referenced by: r19.2zb 4494 intssuni 4973 iinssiun 5009 riinn0 5085 iinexg 5340 reusv2lem2 5396 reusv2lem3 5397 xpiindi 5834 cnviin 6284 eusvobj2 7403 iiner 8785 finsschain 9361 cfeq0 10253 cfsuc 10254 iundom2g 10537 alephval2 10569 prlem934 11030 supaddc 12185 supadd 12186 supmul1 12187 supmullem2 12189 supmul 12190 rexfiuz 15298 r19.2uz 15302 climuni 15500 caurcvg 15627 caurcvg2 15628 caucvg 15629 pc2dvds 16816 vdwmc2 16916 vdwlem6 16923 vdwnnlem3 16934 issubg4 19061 gexcl3 19496 lbsextlem2 20917 iincld 22763 opnnei 22844 cncnp2 23005 lmmo 23104 iunconn 23152 ptbasfi 23305 filuni 23609 isfcls 23733 fclsopn 23738 ustfilxp 23937 nrginvrcn 24429 lebnumlem3 24709 cfil3i 25017 caun0 25029 iscmet3 25041 nulmbl2 25285 dyadmax 25347 itg2seq 25492 itg2monolem1 25500 bddiblnc 25591 rolle 25742 c1lip1 25749 taylfval 26107 ulm0 26139 frgrreg 29914 bnj906 34239 cvmliftlem15 34587 dfon2lem6 35064 filnetlem4 35569 itg2addnclem 36842 itg2addnc 36845 itg2gt0cn 36846 ftc1anc 36872 filbcmb 36911 incsequz 36919 isbnd2 36954 isbnd3 36955 ssbnd 36959 unichnidl 37202 iunconnlem2 43998 upbdrech 44313 infxrpnf 44454 |
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