Metamath Proof Explorer


Theorem speccl

Description: The spectrum of an operator is a set of complex numbers. (Contributed by NM, 11-Apr-2006) (New usage is discouraged.)

Ref Expression
Assertion speccl
|- ( T : ~H --> ~H -> ( Lambda ` T ) C_ CC )

Proof

Step Hyp Ref Expression
1 specval
 |-  ( T : ~H --> ~H -> ( Lambda ` T ) = { x e. CC | -. ( T -op ( x .op ( _I |` ~H ) ) ) : ~H -1-1-> ~H } )
2 ssrab2
 |-  { x e. CC | -. ( T -op ( x .op ( _I |` ~H ) ) ) : ~H -1-1-> ~H } C_ CC
3 1 2 eqsstrdi
 |-  ( T : ~H --> ~H -> ( Lambda ` T ) C_ CC )