Talk:Degenerate elliptic equation

Post-$\TeX$ notes

• I have replaced the $\left\|\cdot\right\|$ on the final line by a $[\cdot]$, since the former seemed to me to be a typo, DE experts please check this ...

--Jjg 00:21, 3 May 2012 (CEST)

The Soviet tradition was to denote the matrix with elements $a_{ij}$ by $\|a_{ij}\|$, sometimes with explicit indication of the limits, $\|a_{ij}\|_{i,j=1}^n$. As far as I am aware, the Western style allows both bracketed forms, $(a_{ij})$ and $[a_{ij}]$. In case of potential confusion, I would add the limits to dispel the ambiguity. -- Sergei Yakovenko 08:27, 3 May 2012 (CEST)

Thank you Sergei, one learns something new every day! I think that the present form (without the explicit indices) is sufficiently common in the West that no confusion will arise.