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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 2528 | . 2 ⊢ (∃𝑥 ∈ 𝐴 𝜑 ↔ ∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑)) | |
| 2 | nfe1 1545 | . 2 ⊢ Ⅎ𝑥∃𝑥(𝑥 ∈ 𝐴 ∧ 𝜑) | |
| 3 | 1, 2 | nfxfr 1523 | 1 ⊢ Ⅎ𝑥∃𝑥 ∈ 𝐴 𝜑 |
| Colors of variables: wff set class |
| Syntax hints: ∧ wa 104 Ⅎwnf 1509 ∃wex 1541 ∈ wcel 2205 ∃wrex 2523 |
| 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 1496 ax-gen 1498 ax-ie1 1542 |
| This theorem depends on definitions: df-bi 117 df-nf 1510 df-rex 2528 |
| This theorem is referenced by: r19.29an 2687 nfiu1 4026 fun11iun 5640 eusvobj2 6044 fodjuomnilemdc 7448 ismkvnex 7459 prarloclem3step 7827 prmuloc2 7898 ltexprlemm 7931 caucvgprprlemaddq 8039 caucvgsrlemgt1 8126 axpre-suploclemres 8232 supinfneg 9945 infsupneg 9946 lbzbi 9966 divalglemeunn 12632 divalglemeuneg 12634 bezoutlemmain 12719 bezout 12732 lss1d 14657 pw1nct 16903 isomninnlem 16940 trirec0 16954 ismkvnnlem 16963 |
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