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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 2534 | . 2 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
| 2 | nfe1 1549 | . 2 ⊢ Ⅎ𝑥∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) | |
| 3 | 1, 2 | nfxfr 1527 | 1 ⊢ Ⅎ𝑥∃𝑥 ∈ 𝐴 𝜑 |
| Colors of variables: wff set class |
| This proof depends on syntax axioms: ∧ wa 104 Ⅎwnf 1513 ∃wex 1545 ∈ wcel 2209 ∃wrex 2529 |
| This proof depends on axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-5 1500 ax-gen 1502 ax-ie1 1546 |
| This proof depends on definitions: df-bi 117 df-nf 1514 df-rex 2534 |
| This theorem is used by: r19.29an 2693 nfiu1 4042 fun11iun 5663 eusvobj2 6074 fodjuomnilemdc 7490 ismkvnex 7501 prarloclem3step 7869 prmuloc2 7940 ltexprlemm 7973 caucvgprprlemaddq 8081 caucvgsrlemgt1 8168 axpre-suploclemres 8274 supinfneg 10011 infsupneg 10012 lbzbi 10032 divalglemeunn 12713 divalglemeuneg 12715 bezoutlemmain 12800 bezout 12813 lss1d 14829 pw1nct 17238 isomninnlem 17285 trirec0 17300 ismkvnnlem 17309 |
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