On Sun, May 15, 2016 at 10:10 AM, Hans Åberg <haberg-1@telia.com> wrote:

> On 14 May 2016, at 23:26, Aditya Mahajan <adityam@umich.edu> wrote:

>>> Use
>>> \startformula\relax
>>> ...
>>> \stopformula
>> Just about anything seems to work:
>> I put in an empty group
>> \startformula{}
>> ...
>> \stopformula
> Be careful with empty group in math mode:
> \startformula{}     -a \stopformula
> \startformula\relax -a \stopformula

A good example, illustrating a difference between \relax and {}, whatever it may be. I used it just to save some typing in a workaround. It must start with an integral sign having at least one limit:
\startformula       ∫_a f φ\stopformula
\startformula{}     ∫_a f φ\stopformula
\startformula\,     ∫_a f φ\stopformula
\startformula\relax ∫_a f φ\stopformula

Without limits, I get too much space after the integral sign:
\startformula       ∫ f φ\stopformula

Maybe it's a little unkown but under 
there is i-formula.xml
$>context i-formula.xml