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Definition df-1st 6399
 Description: Define a function that extracts the first member, or abscissa, of an ordered pair. Theorem op1st 6405 proves that it does this. For example, ?Error: 3 , 4 >. ) = 3 ^ This math symbol is not active (i.e. was not declared in this scope). ( <.3,4>.)=3`. Equivalent to Definition 5.13 (i) of [Monk1] p. 52 (compare op1sta 5397 and op1stb 4799). The notation is the same as Monk's. (Contributed by NM, 9-Oct-2004.)
Assertion
Ref Expression
df-1st

Detailed syntax breakdown of Definition df-1st
StepHypRef Expression
1 c1st 6397 . 2
2 vx . . 3
3 cvv 2965 . . 3
42cv 1653 . . . . . 6
54csn 3841 . . . . 5
65cdm 4919 . . . 4
76cuni 4043 . . 3
82, 3, 7cmpt 4301 . 2
91, 8wceq 1654 1
 Colors of variables: wff set class This definition is referenced by:  1stval  6401  fo1st  6416  f1stres  6418
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