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Definition df-cnv 4889
 Description: Define the converse of a class. Definition 9.12 of [Quine] p. 64. The converse of a binary relation swaps its arguments, i.e., if and then , as proven in brcnv 5058 (see df-br 4216 and df-rel 4888 for more on relations). For example, (ex-cnv 21750). We use Quine's breve accent (smile) notation. Like Quine, we use it as a prefix, which eliminates the need for parentheses. Many authors use the postfix superscript "to the minus one." "Converse" is Quine's terminology; some authors call it "inverse," especially when the argument is a function. (Contributed by NM, 4-Jul-1994.)
Assertion
Ref Expression
df-cnv
Distinct variable group:   ,,

Detailed syntax breakdown of Definition df-cnv
StepHypRef Expression
1 cA . . 3
21ccnv 4880 . 2
3 vy . . . . 5
43cv 1652 . . . 4
5 vx . . . . 5
65cv 1652 . . . 4
74, 6, 1wbr 4215 . . 3
87, 5, 3copab 4268 . 2
92, 8wceq 1653 1
 Colors of variables: wff set class This definition is referenced by:  cnvss  5048  elcnv  5052  nfcnv  5054  opelcnvg  5055  cnvco  5059  relcnv  5245  cnvi  5279  cnvun  5280  cnvcnv3  5323  csbcnvg  24042
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