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| Mirrors > Home > ILE Home > Th. List > nfre1 | GIF version | ||
| Description: 𝑥 is not free in ∃𝑥 ∈ 𝐴𝜑. (Contributed by NM, 19-Mar-1997.) (Revised by Mario Carneiro, 7-Oct-2016.) |
| Ref | Expression |
|---|---|
| nfre1 | ⊢ Ⅎ𝑥∃𝑥 ∈ 𝐴 𝜑 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-rex 2516 | . 2 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
| 2 | nfe1 1544 | . 2 ⊢ Ⅎ𝑥∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) | |
| 3 | 1, 2 | nfxfr 1522 | 1 ⊢ Ⅎ𝑥∃𝑥 ∈ 𝐴 𝜑 |
| Colors of variables: wff set class |
| Syntax hints: ∧ wa 104 Ⅎwnf 1508 ∃wex 1540 ∈ wcel 2202 ∃wrex 2511 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-5 1495 ax-gen 1497 ax-ie1 1541 |
| This theorem depends on definitions: df-bi 117 df-nf 1509 df-rex 2516 |
| This theorem is referenced by: r19.29an 2675 nfiu1 4000 fun11iun 5604 eusvobj2 6004 fodjuomnilemdc 7343 ismkvnex 7354 prarloclem3step 7716 prmuloc2 7787 ltexprlemm 7820 caucvgprprlemaddq 7928 caucvgsrlemgt1 8015 axpre-suploclemres 8121 supinfneg 9829 infsupneg 9830 lbzbi 9850 divalglemeunn 12487 divalglemeuneg 12489 bezoutlemmain 12574 bezout 12587 lss1d 14403 pw1nct 16630 isomninnlem 16660 trirec0 16674 ismkvnnlem 16683 |
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