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I've posted two other questions* $[1]$ $[2]$, discussing and asking about the Tensor Product construction, in particular the "canonical construction", which is the one $[4]$:

$$ \frac{F(V \times W)}{S} := V\otimes W. \tag{1}$$

Now, due to isomorphism $L$ induced by the machinery of tensor product we can say then that the vector space $Z$ and $V\otimes W$ are isomorphic. Therefore, we can say that elements of $Z$ are tensors,i.e. $(V\otimes W, \otimes) \approx (Z, b)$:

$$\begin{array}{rcl} V \times W & \overset{\otimes}{\to} & V \otimes W \\ b & \searrow & \downarrow L \\ \, & \, & Z \end{array} Figure \hspace{1mm}1$$

My doubt is: Since $(V\otimes W, \otimes) \approx (Z, b)$, can I construct another commutative diagram like Figure 2, and say that the pair $(Z, b)$ is the tensor product for another bilinear map $\phi$?

$$\begin{array}{rcl} V \times W & \overset{b}{\to} & Z \\ \phi & \searrow & \downarrow L' \\ \, & \, & \mathbb{R} \end{array} Figure \hspace{1mm}2$$

$$ --- \circ---$$

$*$ I'm not referring my own questions aiming more answers, it's just to show self-study progression.

$[1]$ Doubt on the understanding of the role of Quotient Spaces on Tensor Product construction

$[2]$ Doubt on the notation of the generators of the subspace $S \subset F(V \times W)$ in tensor product construction

$[3]$ Understanding the Details of the Construction of the Tensor Product

$[4]$ ROMAN.S; Advanced Linear Algebra

$[5]$ CONRAD.K; Tensor Products I. https://kconrad.math.uconn.edu/blurbs/linmultialg/tensorprod.pdf

RobPratt
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  • What does"tensor product for another bilinear map $ϕ$" mean? – Noel Lundström Apr 19 '20 at 19:36
  • Means, for example, the inner product map. What I want to know is if I could do what I ask above. Acctually I want more. Suppose that $Z = L(V^{} \times W^{},\mathbb{R})$ the vector space of bilinear forms considering the duals. Then, by tensor product construction we say that elements of $L(V^{} \times W^{},\mathbb{R})$ are tensors because $V\otimes W \approx L(V^{} \times W^{},\mathbb{R})$. – BasicMathGuy Apr 19 '20 at 19:42
  • @NoelLundström also since they are isomorfic, we can say that the pair $(L(V^{} \times W^{},\mathbb{R}), b )$ is a tensor product. Then we can construct another commutative diagram like figure 2, and study bilinear maps like inner product.

    Note that we cannot state that $b = \langle \cdot , \cdot \rangle$ because $Z = L(V^{} \times W^{},\mathbb{R})$. Conversely, we cannot say that $V\otimesW = L(V^{} \times W^{},\mathbb{R}) $ in the first place, because we need to construct the tensor product.

    – BasicMathGuy Apr 19 '20 at 19:46
  • in your formula (1) it should be $=:$ instead – janmarqz Apr 20 '20 at 18:53

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