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Definition df-lsw 12230
Description: Extract the last symbol of a word. May be not meaningful for other sets which are not words. The name lastS (as abbreviation of "lastSymbol") is a compromise between usually used names for corresponding functions in computer programs (as last() or lastChar()), the terminology used for words in set.mm ("symbol" instead of "character") and brevity ("lastS" is shorter than "lastChar" and "lastSymbol"). Labels of theorems about last symbols of a word will contain the abbreviation "lsw" (Last Symbol of a Word). (Contributed by Alexander van der Vekens, 18-Mar-2018.)
Assertion
Ref Expression
df-lsw  |- lastS  =  ( w  e.  _V  |->  ( w `  ( (
# `  w )  -  1 ) ) )

Detailed syntax breakdown of Definition df-lsw
StepHypRef Expression
1 clsw 12222 . 2  class lastS
2 vw . . 3  setvar  w
3 cvv 2972 . . 3  class  _V
42cv 1368 . . . . . 6  class  w
5 chash 12103 . . . . . 6  class  #
64, 5cfv 5418 . . . . 5  class  ( # `  w )
7 c1 9283 . . . . 5  class  1
8 cmin 9595 . . . . 5  class  -
96, 7, 8co 6091 . . . 4  class  ( (
# `  w )  -  1 )
109, 4cfv 5418 . . 3  class  ( w `
 ( ( # `  w )  -  1 ) )
112, 3, 10cmpt 4350 . 2  class  ( w  e.  _V  |->  ( w `
 ( ( # `  w )  -  1 ) ) )
121, 11wceq 1369 1  wff lastS  =  ( w  e.  _V  |->  ( w `  ( (
# `  w )  -  1 ) ) )
Colors of variables: wff setvar class
This definition is referenced by:  lsw  12266  sseqval  26771  sseqfv1  26772  sseqfn  26773  sseqf  26775  sseqfv2  26777
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