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| Mirrors > Home > ILE Home > Th. List > df-nel | GIF version | ||
| Description: Define negated membership. (Contributed by NM, 7-Aug-1994.) |
| Ref | Expression |
|---|---|
| df-nel | ⊢ (𝐴 ∉ 𝐵 ↔ ¬ 𝐴 ∈ 𝐵) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cA | . . 3 class 𝐴 | |
| 2 | cB | . . 3 class 𝐵 | |
| 3 | 1, 2 | wnel 2462 | . 2 wff 𝐴 ∉ 𝐵 |
| 4 | 1, 2 | wcel 2167 | . . 3 wff 𝐴 ∈ 𝐵 |
| 5 | 4 | wn 3 | . 2 wff ¬ 𝐴 ∈ 𝐵 |
| 6 | 3, 5 | wb 105 | 1 wff (𝐴 ∉ 𝐵 ↔ ¬ 𝐴 ∈ 𝐵) |
| Colors of variables: wff set class |
| This definition is referenced by: neli 2464 nelir 2465 neleq1 2466 neleq2 2467 nfnel 2469 nfneld 2470 elnelne1 2471 elnelne2 2472 nelcon3d 2473 elnelall 2474 ru 2988 sbcnel12g 3101 raldifb 3304 pwnss 4193 pwnex 4485 ruALT 4588 0nelrel 4710 fiprc 6883 0mnnnnn0 9298 nelfzo 10244 fvinim0ffz 10334 wrdlndm 10969 wrdsymb0 10984 rennim 11184 fsumsplitsnun 11601 modfsummodlemstep 11639 sqrt2irr0 12357 isnsgrp 13108 bdnel 15584 |
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