Pretty trivial but for a matrix
\begin{bmatrix}x&x&\ldots&x&x\\x&x&\ldots&x&x\\\vdots&\vdots&\ddots&x&x\\x&x&\ldots&x&x\end{bmatrix}
with $N\times N $, is there is simpler notation. I had $A=[x_{i,j}]\in \Bbb R^{N\times N}$ in my mind, but I can't find anywhere were it is used
Edit: I forgot to mention but, I need to work with the elements in the matrix, so like doing scalar multiplication (to do a proof by the principle of mathematical induction question). But it a $3\times 3$ so I figured out I do have to write every single element 9 times in a row. Is there any notation that can make my math simpler?
Best Answer
Assuming that $x \neq 0$, it's a rank-$1$ matrix. Thus, to emphasize its rank-$1$-ness, I would use
$$\color{blue}{x \,{\Bbb 1}_n {\Bbb 1}_n^\top}$$