On Wed, 10 Apr 2019, Hans Hagen wrote:

> On 4/10/2019 9:40 AM, Mikael P. Sundqvist wrote:
>> On Wed, Apr 10, 2019 at 9:21 AM Otared Kavian <otared@gmail.com> wrote:
>>> 
>>> Hi Hans,
>>> 
>>> While testing old documents with lmtx, I noticed that with recent versions 
>>> of mkiv, as well as LuaMetaTeX, there is a strange behavior in math mode: 
>>> when the characters < and - follow each other one gets \leftarrow… This is 
>>> embarrassing when one writes inequalities for negative numbers.
>>> So one has to separate them in order to obtain with curly braces. Can this 
>>> be fixed or is it intended ?
>>> 
>>> \starttext
>>> $\alpha < -1$
>>> 
>>> $\alpha \leftarrow 1$
>>> 
>>> $\alpha < {-1}$
>>> 
>>> $\alpha {<} - 1$
>>> \stoptext
>>> 
>>> Best regards: OK
>> 
>> Hi!
>> 
>> I asked about this before, and it is a feature.
>> 
>> It can be switched off with
>> 
>> \setupmathematics[
>> collapsing=1,
>> ]
>> 
>> Hope it helps!
> Indeed. Aditya is in charge of decisions about these defaults so if you want 
> it differently you need to convince him. (I'm not sure how many users depend 
> on it.)

We can turn it off by default. But it might be better to have a more 
versbose interface:

   \setupmathematics[collapsing=yes|no]

with the default value being collapsing=no.

Aditya