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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 2514 | . 2 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
| 2 | nfe1 1542 | . 2 ⊢ Ⅎ𝑥∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) | |
| 3 | 1, 2 | nfxfr 1520 | 1 ⊢ Ⅎ𝑥∃𝑥 ∈ 𝐴 𝜑 |
| Colors of variables: wff set class |
| Syntax hints: ∧ wa 104 Ⅎwnf 1506 ∃wex 1538 ∈ wcel 2200 ∃wrex 2509 |
| 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 1493 ax-gen 1495 ax-ie1 1539 |
| This theorem depends on definitions: df-bi 117 df-nf 1507 df-rex 2514 |
| This theorem is referenced by: r19.29an 2673 nfiu1 3995 fun11iun 5595 eusvobj2 5993 fodjuomnilemdc 7322 ismkvnex 7333 prarloclem3step 7694 prmuloc2 7765 ltexprlemm 7798 caucvgprprlemaddq 7906 caucvgsrlemgt1 7993 axpre-suploclemres 8099 supinfneg 9802 infsupneg 9803 lbzbi 9823 divalglemeunn 12447 divalglemeuneg 12449 bezoutlemmain 12534 bezout 12547 lss1d 14362 pw1nct 16428 isomninnlem 16458 trirec0 16472 ismkvnnlem 16480 |
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