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Definition df-tail 16428
Description: Define the tail function for directed sets. (Contributed by Jeff Hankins, 25-Nov-2009.)
Assertion
Ref Expression
df-tail  |-  tail  =  ( r  e.  DirRel  |->  ( x  e.  U. U. r  |->  ( r " { x } ) ) )
Distinct variable group:    x, r

Detailed syntax breakdown of Definition df-tail
StepHypRef Expression
1 ctail 16426 . 2  class  tail
2 vr . . 3  setvar  r
3 cdir 16425 . . 3  class  DirRel
4 vx . . . 4  setvar  x
52cv 1436 . . . . . 6  class  r
65cuni 4222 . . . . 5  class  U. r
76cuni 4222 . . . 4  class  U. U. r
84cv 1436 . . . . . 6  class  x
98csn 4002 . . . . 5  class  { x }
105, 9cima 4857 . . . 4  class  ( r
" { x }
)
114, 7, 10cmpt 4484 . . 3  class  ( x  e.  U. U. r  |->  ( r " {
x } ) )
122, 3, 11cmpt 4484 . 2  class  ( r  e.  DirRel  |->  ( x  e. 
U. U. r  |->  ( r
" { x }
) ) )
131, 12wceq 1437 1  wff  tail  =  ( r  e.  DirRel  |->  ( x  e.  U. U. r  |->  ( r " { x } ) ) )
Colors of variables: wff setvar class
This definition is referenced by:  tailfval  30813
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