if tail = [] then
P.Mn (attr,value)
else P.Mrow ([],P.Mn (attr,value)::tail)
| CE.Appl (axref,CE.Symbol(sxref,n,subst,uri)::tl) ->
if tail = [] then
P.Mn (attr,value)
else P.Mrow ([],P.Mn (attr,value)::tail)
| CE.Appl (axref,CE.Symbol(sxref,n,subst,uri)::tl) ->