Let us consider a transformation $T$, which converts a vector into a symmetric matrix, e.g.
Xh=[x1,x2,x3]T
, then \(T(X_h) =.
I want to have this type of decomposition:
T(QXh)=Q¯T(Xh)Q¯T.
Here, $Q\in \mathbb{R}^{m\times \frac{q(q+1)}{2}}$, $\bar{Q}\in \mathbb{R}^{p \times q}$, $T(X_h)\in \mathbb{R}^{q \times q}$ and $X_h \in \mathbb{R}^{q(q+1)/2}$.
For example:
Consider a known constant matrix $Q \in \mathrm{R}^{10 \times 3}$. A vector $X_h = [x_{11}, x_{12}, x_{22}]^T \in \mathrm{R}^3$.
Decomposition must be like,
T(QXh)=Q¯T(Xh)Q¯T=Q¯[x11x12x12x22]Q¯T
where, $T(QX_h)\in \mathrm{R}^{4 \times 4}$, $\bar{Q}\in \mathrm{R}^{4 \times 2}$ and $T(X_h)\in \mathrm{R}^{2\times 2}$
Given $Q$, I want to find $\bar{Q}$ such that the equation holds for all $X_h$.
Is such decomposition possible?
