> Hans Aberg <mailto:haberg-1@telia.com>
> 6. Juli 2015 11:24
> The example below shows the intended output when using original TeX 
> code (compiled with ‘context' of TeX Live 2015): a pair of left braced 
> formulas. The first comment shows what works in AMS-LaTeX.
>
> However, when trying similar ConTeXt commands, I get the error shown 
> in the comment below. What ConTeXt command might use here?

Take a look at the wiki page [1] for multiline equations and also the 
linked PDF at the start of the page.

[1] http://wiki.contextgarden.net/Multiline_equations#Cases

Wolfgang