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| Mirrors > Home > NFE Home > Th. List > nfrab | Unicode version | ||
| Description: A variable not free in a wff remains so in a restricted class abstraction. (Contributed by NM, 13-Oct-2003.) (Revised by Mario Carneiro, 9-Oct-2016.) | 
| Ref | Expression | 
|---|---|
| nfrab.1 | 
 | 
| nfrab.2 | 
 | 
| Ref | Expression | 
|---|---|
| nfrab | 
 | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | df-rab 2624 | 
. 2
 | |
| 2 | nftru 1554 | 
. . . 4
 | |
| 3 | nfrab.2 | 
. . . . . . . 8
 | |
| 4 | 3 | nfcri 2484 | 
. . . . . . 7
 | 
| 5 | eleq1 2413 | 
. . . . . . 7
 | |
| 6 | 4, 5 | dvelimnf 2017 | 
. . . . . 6
 | 
| 7 | nfrab.1 | 
. . . . . . 7
 | |
| 8 | 7 | a1i 10 | 
. . . . . 6
 | 
| 9 | 6, 8 | nfand 1822 | 
. . . . 5
 | 
| 10 | 9 | adantl 452 | 
. . . 4
 | 
| 11 | 2, 10 | nfabd2 2508 | 
. . 3
 | 
| 12 | 11 | trud 1323 | 
. 2
 | 
| 13 | 1, 12 | nfcxfr 2487 | 
1
 | 
| Colors of variables: wff setvar class | 
| Syntax hints:    | 
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1546 ax-5 1557 ax-17 1616 ax-9 1654 ax-8 1675 ax-6 1729 ax-7 1734 ax-11 1746 ax-12 1925 ax-ext 2334 | 
| This theorem depends on definitions: df-bi 177 df-or 359 df-an 360 df-tru 1319 df-ex 1542 df-nf 1545 df-sb 1649 df-clab 2340 df-cleq 2346 df-clel 2349 df-nfc 2479 df-rab 2624 | 
| This theorem is referenced by: (None) | 
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