mstack and south carries

Hi all,



The MathML specification allows specifying carries at south positions. In
this case, when other rows of carries exists it is not clear how the
formula must be rendered.



For example, in the following formula

<mstack><mscarries><mn>1</mn></mscarries><mscarries
location="s"><mn>2</mn></mscarries><mn>3</mn><msline/><msrow/></mstack>



What’s is the expected rendering?

1



3

2



Or maybe



1

3

2



?





Dani