$\begingroup$
$\endgroup$
5
Is there a convention to write the all ones matrix in formulas? I'm going to write about the following formular:
$$ A = B + XD + DX + N $$
Where D is a diagonal matrix and X the all ones matrix:
$$ X = \begin{pmatrix} 1 & 1 & \cdots & 1 \\ 1 & 1 & \cdots & 1 \\ \vdots & \vdots & \ddots & \vdots \\ 1 & 1 & \cdots & 1 \end{pmatrix} $$
Is there a greek letter or other convention?
1 Answer
$\begingroup$
$\endgroup$
Yes, I have seen the $n\times n$ all-ones matrix denoted $J_n$. I think this is somewhat conventional in algebraic combinatorics, but I have no idea whether it is commonly used elsewhere.
