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Mirrors > Home > NFE Home > Th. List > df-ov | GIF version |
Description: Define the value of an operation. Definition of operation value in [Enderton] p. 79. Note that the syntax is simply three class expressions in a row bracketed by parentheses. There are no restrictions of any kind on what those class expressions may be, although only certain kinds of class expressions - a binary operation F and its arguments A and B- will be useful for proving meaningful theorems. This definition is well-defined, although not very meaningful, when classes A and/or B are proper classes (i.e. are not sets). On the other hand, we often find uses for this definition when F is a proper class. F is normally equal to a class of nested ordered pairs of the form defined by df-oprab 5529. (Contributed by SF, 5-Jan-2015.) |
Ref | Expression |
---|---|
df-ov | ⊢ (AFB) = (F ‘〈A, B〉) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cA | . . 3 class A | |
2 | cB | . . 3 class B | |
3 | cF | . . 3 class F | |
4 | 1, 2, 3 | co 5526 | . 2 class (AFB) |
5 | 1, 2 | cop 4562 | . . 3 class 〈A, B〉 |
6 | 5, 3 | cfv 4782 | . 2 class (F ‘〈A, B〉) |
7 | 4, 6 | wceq 1642 | 1 wff (AFB) = (F ‘〈A, B〉) |
Colors of variables: wff setvar class |
This definition is referenced by: oveq 5530 oveq1 5531 oveq2 5532 nfovd 5545 ovex 5552 fnopovb 5558 ffnov 5588 eqfnov 5590 fnov 5592 ovidig 5594 ov 5596 ovigg 5597 ov6g 5601 ovg 5602 ovres 5603 fovrn 5605 fnrnov 5606 foov 5607 fnovrn 5608 funimassov 5610 ovelimab 5611 ovconst2 5612 oprssdm 5613 ndmovg 5614 ndmovcl 5615 ndmov 5616 elovex12 5649 brcupg 5815 brcomposeg 5820 braddcfn 5827 brcrossg 5849 brfullfunop 5868 fce 6189 |
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