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| Mirrors > Home > MPE Home > Th. List > Mathboxes > df-domain | Structured version Visualization version GIF version | ||
| Description: Define the domain function. See brdomain 35934 for its value. (Contributed by Scott Fenton, 11-Apr-2014.) | 
| Ref | Expression | 
|---|---|
| df-domain | ⊢ Domain = Image(1st ↾ (V × V)) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cdomain 35844 | . 2 class Domain | |
| 2 | c1st 8012 | . . . 4 class 1st | |
| 3 | cvv 3480 | . . . . 5 class V | |
| 4 | 3, 3 | cxp 5683 | . . . 4 class (V × V) | 
| 5 | 2, 4 | cres 5687 | . . 3 class (1st ↾ (V × V)) | 
| 6 | 5 | cimage 35841 | . 2 class Image(1st ↾ (V × V)) | 
| 7 | 1, 6 | wceq 1540 | 1 wff Domain = Image(1st ↾ (V × V)) | 
| Colors of variables: wff setvar class | 
| This definition is referenced by: brdomain 35934 | 
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