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Mirrors > Home > ILE Home > Th. List > df-1st | Unicode version |
Description: Define a function that extracts the first member, or abscissa, of an ordered pair. Theorem op1st 5715 proves that it does this. For example, ( 3 , 4 ) = 3 . Equivalent to Definition 5.13 (i) of [Monk1] p. 52 (compare op1sta 4745 and op1stb 4175). The notation is the same as Monk's. (Contributed by NM, 9-Oct-2004.) |
Ref | Expression |
---|---|
df-1st |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | c1st 5707 | . 2 | |
2 | vx | . . 3 | |
3 | cvv 2551 | . . 3 | |
4 | 2 | cv 1241 | . . . . . 6 |
5 | 4 | csn 3367 | . . . . 5 |
6 | 5 | cdm 4288 | . . . 4 |
7 | 6 | cuni 3571 | . . 3 |
8 | 2, 3, 7 | cmpt 3809 | . 2 |
9 | 1, 8 | wceq 1242 | 1 |
Colors of variables: wff set class |
This definition is referenced by: 1stvalg 5711 fo1st 5726 f1stres 5728 |
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