Hello! I tried the modules t-amsl and t-nath. This is what I noticed or have questions about: 1. The bracket for \cases{} is too small when t-nath is used, as in this example: \usemodule[amsl] \usemodule[nath] \starttext We denote by \startformula 1_{ij} = \cases{ 1 & if $(i,j) \in \cal E$\cr 0 & else} \stopformula the {\em indicator function} of event $(i,j) \in \cal E$. \stoptext Without modules amsl and nath the brackets have correct size, but \cal has no effect. 2. Without module amsl, the above example produces an error message. 3. Module amsl uses \mathBbd{} for the blackboard fonts. I'm not sure if this is used in AMS-Latex, however neither amsmath nor amssymb introduce this command. Instead, there's a command \mathbb{} in amssymb for the blackboard fonts. 4. $\mathBbd{N}_0$ doesn't produce ${\mb N}_0$. Boris Hollas