Metamath Proof Explorer


Definition df-hnorm

Description: Define the function for the norm of a vector of Hilbert space. See normval for its value and normcl for its closure. Theorems norm-i-i , norm-ii-i , and norm-iii-i show it has the expected properties of a norm. In the literature, the norm of A is usually written "|| A ||", but we use function notation to take advantage of our existing theorems about functions. Definition of norm in Beran p. 96. (Contributed by NM, 6-Jun-2008) (New usage is discouraged.)

Ref Expression
Assertion df-hnorm
|- normh = ( x e. dom dom .ih |-> ( sqrt ` ( x .ih x ) ) )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cno
 |-  normh
1 vx
 |-  x
2 csp
 |-  .ih
3 2 cdm
 |-  dom .ih
4 3 cdm
 |-  dom dom .ih
5 csqrt
 |-  sqrt
6 1 cv
 |-  x
7 6 6 2 co
 |-  ( x .ih x )
8 7 5 cfv
 |-  ( sqrt ` ( x .ih x ) )
9 1 4 8 cmpt
 |-  ( x e. dom dom .ih |-> ( sqrt ` ( x .ih x ) ) )
10 0 9 wceq
 |-  normh = ( x e. dom dom .ih |-> ( sqrt ` ( x .ih x ) ) )