In case you don't need to use dashed lines inside a kbordermatrix
, you can obtain the same result with the blockarray
environment – in a less simple way (but you may define new commands/ environments), and it is compatible with arydshln
as long as you don't use inside blockarray.
So I propose this code as a work-around:
\documentclass{article}
\usepackage{amsmath}
\usepackage{kbordermatrix}
\usepackage{array, blkarray} %
\usepackage{arydshln}
\newcolumntype{$}{>{\global\let\currentrowstyle\relax}}
\newcolumntype{^}{>{\currentrowstyle}}
\newcommand{\rowstyle}[1]{\gdef\currentrowstyle{#1}%
#1\ignorespaces
}
\begin{document}
\begin{align}
\begin{blockarray}{*{3}{>{\scriptstyle}c}}
1 & 2 & 3\\
\begin{block}{\Left{$ \scriptstyle a $\enspace }{[\enspace}ccc\Right{. \enspace]}{}}
b & c & d\\
\end{block}
\end{blockarray}
\end{align}
\begin{align}
\begin{array}{$c*{3}{^c}}
\rowstyle{\scriptstyle} & 1 & 2 & 3\\
\hdashline
\scriptstyle a & b & c & d
\end{array}
\end{align}
\end{document}
