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| Mirrors > Home > NFE Home > Th. List > df-dif | Unicode version | ||
| Description: Define the difference of two classes. See eldif 3222 for membership. (Contributed by SF, 10-Jan-2015.) | 
| Ref | Expression | 
|---|---|
| df-dif | 
 | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cA | 
. . 3
 | |
| 2 | cB | 
. . 3
 | |
| 3 | 1, 2 | cdif 3207 | 
. 2
 | 
| 4 | 2 | ccompl 3206 | 
. . 3
 | 
| 5 | 1, 4 | cin 3209 | 
. 2
 | 
| 6 | 3, 5 | wceq 1642 | 
1
 | 
| Colors of variables: wff setvar class | 
| This definition is referenced by: eldif 3222 nfdif 3233 difeq1 3247 difeq2 3248 difsscompl 3550 compldif 4070 inindif 4076 difexg 4103 nnsucelrlem3 4427 ssfin 4471 sbthlem1 6204 | 
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