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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 6003 fodjuomnilemdc 7342 ismkvnex 7353 prarloclem3step 7715 prmuloc2 7786 ltexprlemm 7819 caucvgprprlemaddq 7927 caucvgsrlemgt1 8014 axpre-suploclemres 8120 supinfneg 9828 infsupneg 9829 lbzbi 9849 divalglemeunn 12481 divalglemeuneg 12483 bezoutlemmain 12568 bezout 12581 lss1d 14396 pw1nct 16604 isomninnlem 16634 trirec0 16648 ismkvnnlem 16656 |
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