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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 1981). 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 3063 | . . . 4 ⊢ (∀𝑥 ∈ 𝐴 𝜑 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝜑)) | |
2 | exintr 1896 | . . . 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 3072 | . . 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 409 | 1 ⊢ ((𝐴 ≠ ∅ ∧ ∀𝑥 ∈ 𝐴 𝜑) → ∃𝑥 ∈ 𝐴 𝜑) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 397 ∀wal 1540 ∃wex 1782 ∈ wcel 2107 ≠ wne 2941 ∀wral 3062 ∃wrex 3071 ∅c0 4322 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-9 2117 ax-ext 2704 |
This theorem depends on definitions: df-bi 206 df-an 398 df-tru 1545 df-fal 1555 df-ex 1783 df-sb 2069 df-clab 2711 df-cleq 2725 df-ne 2942 df-ral 3063 df-rex 3072 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 5834 cnviin 6283 eusvobj2 7398 iiner 8780 finsschain 9356 cfeq0 10248 cfsuc 10249 iundom2g 10532 alephval2 10564 prlem934 11025 supaddc 12178 supadd 12179 supmul1 12180 supmullem2 12182 supmul 12183 rexfiuz 15291 r19.2uz 15295 climuni 15493 caurcvg 15620 caurcvg2 15621 caucvg 15622 pc2dvds 16809 vdwmc2 16909 vdwlem6 16916 vdwnnlem3 16927 issubg4 19020 gexcl3 19450 lbsextlem2 20765 iincld 22535 opnnei 22616 cncnp2 22777 lmmo 22876 iunconn 22924 ptbasfi 23077 filuni 23381 isfcls 23505 fclsopn 23510 ustfilxp 23709 nrginvrcn 24201 lebnumlem3 24471 cfil3i 24778 caun0 24790 iscmet3 24802 nulmbl2 25045 dyadmax 25107 itg2seq 25252 itg2monolem1 25260 bddiblnc 25351 rolle 25499 c1lip1 25506 taylfval 25863 ulm0 25895 frgrreg 29637 bnj906 33930 cvmliftlem15 34278 dfon2lem6 34749 filnetlem4 35255 itg2addnclem 36528 itg2addnc 36531 itg2gt0cn 36532 ftc1anc 36558 filbcmb 36597 incsequz 36605 isbnd2 36640 isbnd3 36641 ssbnd 36645 unichnidl 36888 iunconnlem2 43682 upbdrech 44002 infxrpnf 44143 |
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