Metamath Proof Explorer


Theorem adjbdlnb

Description: An operator is bounded and linear iff its adjoint is. (Contributed by NM, 19-Feb-2006) (New usage is discouraged.)

Ref Expression
Assertion adjbdlnb ( 𝑇 ∈ BndLinOp ↔ ( adj𝑇 ) ∈ BndLinOp )

Proof

Step Hyp Ref Expression
1 adjbdln ( 𝑇 ∈ BndLinOp → ( adj𝑇 ) ∈ BndLinOp )
2 bdopadj ( ( adj𝑇 ) ∈ BndLinOp → ( adj𝑇 ) ∈ dom adj )
3 dmadjrnb ( 𝑇 ∈ dom adj ↔ ( adj𝑇 ) ∈ dom adj )
4 2 3 sylibr ( ( adj𝑇 ) ∈ BndLinOp → 𝑇 ∈ dom adj )
5 cnvadj adj = adj
6 5 fveq1i ( adj ‘ ( adj𝑇 ) ) = ( adj ‘ ( adj𝑇 ) )
7 adj1o adj : dom adj1-1-onto→ dom adj
8 simpl ( ( 𝑇 ∈ dom adj ∧ ( adj𝑇 ) ∈ BndLinOp ) → 𝑇 ∈ dom adj )
9 f1ocnvfv1 ( ( adj : dom adj1-1-onto→ dom adj𝑇 ∈ dom adj ) → ( adj ‘ ( adj𝑇 ) ) = 𝑇 )
10 7 8 9 sylancr ( ( 𝑇 ∈ dom adj ∧ ( adj𝑇 ) ∈ BndLinOp ) → ( adj ‘ ( adj𝑇 ) ) = 𝑇 )
11 6 10 eqtr3id ( ( 𝑇 ∈ dom adj ∧ ( adj𝑇 ) ∈ BndLinOp ) → ( adj ‘ ( adj𝑇 ) ) = 𝑇 )
12 adjbdln ( ( adj𝑇 ) ∈ BndLinOp → ( adj ‘ ( adj𝑇 ) ) ∈ BndLinOp )
13 12 adantl ( ( 𝑇 ∈ dom adj ∧ ( adj𝑇 ) ∈ BndLinOp ) → ( adj ‘ ( adj𝑇 ) ) ∈ BndLinOp )
14 11 13 eqeltrrd ( ( 𝑇 ∈ dom adj ∧ ( adj𝑇 ) ∈ BndLinOp ) → 𝑇 ∈ BndLinOp )
15 4 14 mpancom ( ( adj𝑇 ) ∈ BndLinOp → 𝑇 ∈ BndLinOp )
16 1 15 impbii ( 𝑇 ∈ BndLinOp ↔ ( adj𝑇 ) ∈ BndLinOp )