Let
- F∈{C,R}
- X and Y be normed F-vector spaces
- X′ denote the topological dual space of X
- L(X,Y) denote the space of bounded, linear operators from X to Y
- B(X′×Y,F) be the space of bilinear forms on X′×Y
- X⊗Y denote the tensor product of X and Y
Can we show that X′⊗Y can be embedded into L(X,Y), i.e. that there is a
- injective,
- continuous and
- open
mapping ι:X′⊗Y→ι(X′⊗Y)?
Clearly, we would need to choose a norm on X′⊗Y:=span{φ⊗y:(φ,y)∈X′×Y}, where (φ⊗y)(A):=A(φ,y)for B∈B(X′×Y,F). I think that the projective norm π(u):=inf will do it.
My idea is to define (\iota u)(x):=\sum_{i=1}^n\varphi_i(x)y_i\;\;\;\text{for }x\in X\tag 1 for u\in X'\otimes Y with u=\sum_{i=1}^n\varphi_i\otimes y_i.
This \iota is obviously linear. Maybe we can show that it is bounded too (i.e. a bounded, linear operator). This would yield (2.). How can we show this and how can we show (1.) and (3.)?
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