# [NTG-context] Strange behavior in math mode: < and minus sign give leftarrow

Wed Apr 10 14:19:51 CEST 2019

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 at 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!
>>
>>
>> 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.