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Definition df-nmo 22512
Description: Define the norm of an operator between two normed groups (usually vector spaces). This definition produces an operator norm function for each pair of groups  <. s ,  t
>.. Equivalent to the definition of linear operator norm in [AkhiezerGlazman] p. 39. (Contributed by Mario Carneiro, 18-Oct-2015.) (Revised by AV, 25-Sep-2020.)
Assertion
Ref Expression
df-nmo  |-  normOp  =  ( s  e. NrmGrp ,  t  e. NrmGrp  |->  ( f  e.  ( s  GrpHom  t )  |-> inf ( { r  e.  ( 0 [,) +oo )  |  A. x  e.  (
Base `  s )
( ( norm `  t
) `  ( f `  x ) )  <_ 
( r  x.  (
( norm `  s ) `  x ) ) } ,  RR* ,  <  )
) )
Distinct variable group:    f, r, s, t, x

Detailed syntax breakdown of Definition df-nmo
StepHypRef Expression
1 cnmo 22509 . 2  class  normOp
2 vs . . 3  setvar  s
3 vt . . 3  setvar  t
4 cngp 22382 . . 3  class NrmGrp
5 vf . . . 4  setvar  f
62cv 1482 . . . . 5  class  s
73cv 1482 . . . . 5  class  t
8 cghm 17657 . . . . 5  class  GrpHom
96, 7, 8co 6650 . . . 4  class  ( s 
GrpHom  t )
10 vx . . . . . . . . . . 11  setvar  x
1110cv 1482 . . . . . . . . . 10  class  x
125cv 1482 . . . . . . . . . 10  class  f
1311, 12cfv 5888 . . . . . . . . 9  class  ( f `
 x )
14 cnm 22381 . . . . . . . . . 10  class  norm
157, 14cfv 5888 . . . . . . . . 9  class  ( norm `  t )
1613, 15cfv 5888 . . . . . . . 8  class  ( (
norm `  t ) `  ( f `  x
) )
17 vr . . . . . . . . . 10  setvar  r
1817cv 1482 . . . . . . . . 9  class  r
196, 14cfv 5888 . . . . . . . . . 10  class  ( norm `  s )
2011, 19cfv 5888 . . . . . . . . 9  class  ( (
norm `  s ) `  x )
21 cmul 9941 . . . . . . . . 9  class  x.
2218, 20, 21co 6650 . . . . . . . 8  class  ( r  x.  ( ( norm `  s ) `  x
) )
23 cle 10075 . . . . . . . 8  class  <_
2416, 22, 23wbr 4653 . . . . . . 7  wff  ( (
norm `  t ) `  ( f `  x
) )  <_  (
r  x.  ( (
norm `  s ) `  x ) )
25 cbs 15857 . . . . . . . 8  class  Base
266, 25cfv 5888 . . . . . . 7  class  ( Base `  s )
2724, 10, 26wral 2912 . . . . . 6  wff  A. x  e.  ( Base `  s
) ( ( norm `  t ) `  (
f `  x )
)  <_  ( r  x.  ( ( norm `  s
) `  x )
)
28 cc0 9936 . . . . . . 7  class  0
29 cpnf 10071 . . . . . . 7  class +oo
30 cico 12177 . . . . . . 7  class  [,)
3128, 29, 30co 6650 . . . . . 6  class  ( 0 [,) +oo )
3227, 17, 31crab 2916 . . . . 5  class  { r  e.  ( 0 [,) +oo )  |  A. x  e.  ( Base `  s ) ( (
norm `  t ) `  ( f `  x
) )  <_  (
r  x.  ( (
norm `  s ) `  x ) ) }
33 cxr 10073 . . . . 5  class  RR*
34 clt 10074 . . . . 5  class  <
3532, 33, 34cinf 8347 . . . 4  class inf ( { r  e.  ( 0 [,) +oo )  | 
A. x  e.  (
Base `  s )
( ( norm `  t
) `  ( f `  x ) )  <_ 
( r  x.  (
( norm `  s ) `  x ) ) } ,  RR* ,  <  )
365, 9, 35cmpt 4729 . . 3  class  ( f  e.  ( s  GrpHom  t )  |-> inf ( { r  e.  ( 0 [,) +oo )  |  A. x  e.  ( Base `  s ) ( (
norm `  t ) `  ( f `  x
) )  <_  (
r  x.  ( (
norm `  s ) `  x ) ) } ,  RR* ,  <  )
)
372, 3, 4, 4, 36cmpt2 6652 . 2  class  ( s  e. NrmGrp ,  t  e. NrmGrp  |->  ( f  e.  ( s  GrpHom  t )  |-> inf ( { r  e.  ( 0 [,) +oo )  |  A. x  e.  (
Base `  s )
( ( norm `  t
) `  ( f `  x ) )  <_ 
( r  x.  (
( norm `  s ) `  x ) ) } ,  RR* ,  <  )
) )
381, 37wceq 1483 1  wff  normOp  =  ( s  e. NrmGrp ,  t  e. NrmGrp  |->  ( f  e.  ( s  GrpHom  t )  |-> inf ( { r  e.  ( 0 [,) +oo )  |  A. x  e.  (
Base `  s )
( ( norm `  t
) `  ( f `  x ) )  <_ 
( r  x.  (
( norm `  s ) `  x ) ) } ,  RR* ,  <  )
) )
Colors of variables: wff setvar class
This definition is referenced by:  nmoffn  22515  nmofval  22518
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