On Mon, 19 Jan 2009, Otared Kavian wrote:

Hi everyone,

This question is primarily intended for Aditya… but I guess other fellows on the list can also help me solve the following alignment problem: Is it possible to have an alignment like the rsult of the following with \startcases...\stopcases?

\starttext

\startformula \startmatrix[align={right,left,right},distance=3pt,left={\left\{}, right={\right.}] \NC -\Delta u + g(u) \NC{} = f \NC \quad\mbox{in } \Omega\NR \NC \displaystyle {\partial u \over \partial {\bf n} } \NC{} = h(u) \NC \quad\mbox{on } \partial\Omega \NR \stopmatrix \stopformula

\stoptext

Actually I used to have such alignments with the following structure (in good old plain TeX...):

\starttext

\startformula \cases{ \eqalign{ -\Delta u + g(u) &= f \cr \displaystyle {\partial u \over \partial {\bf n} } &= h(u) \cr } \quad \eqalign{ &\hbox{in } \Omega \cr &\vphantom{{\partial u \over \partial {\bf n} }} \hbox{on } \partial\Omega \cr } } \stopformula

\stoptext

(which gives approximately the same result as the first example above, but clearly the math-alignment structure set up by Aditya and Hans is much more elegant. (Although I prefer the vertical distance between the lines obtained with my plain TeX structure: by the way is it possible to fine tune such things in ConTeXt). So my question is: whether one can use \startcases ...\stopcases instead of \startmatrix ... \stopmatrix in order to obtain the result of the plain TeX example?

No, but there is not much difference between cases and matrix. Consider: \definemathmatrix[alignedcase] [align={right,left,right},distance=3pt,left={\left\{}, right={\right.},style=\displaystyle] \starttext \startformula \startalignedcase \NC -\Delta u + g(u) \NC{} = f \NC \quad\mbox{in } \Omega\NR \NC {\partial u \over \partial {\bf n} } \NC{} = h(u) \NC \quad\mbox{on } \partial\Omega \NR \stopalignedcase \stopformula Aditya