In http://wiki.axiom-developer.org/axiom--test--1/src/algebra/OutformSpad supersub(a,[sub1,super1,sub2,super2,...]) is defined as:

  creates a form with each subscript aligned
  under each superscript.

but it is not implemented as one of the specialOps in http://wiki.axiom-developer.org/axiom--test--1/src/algebra/TexSpad see for example:

  op = "SUPERSUB" =>
    ...

As a result these sub/super-scripted symbols are not displayed properly in LaTeX form:

(1) -> )set output algebra on
 

)set expose add constructor OutputForm

   OutputForm is now explicitly exposed in frame initial

supersub(message "M", [q, paren(s)])

         (s)
   (1)  M
         q

(1)