I am using context minimals, with the simpleslides module to make a presentation. I noticed that when typesetting math formulas, I get missing characters. I finally tracked it down to an issue (stupidity from me?) with the "context" executable. I made a new file, with some example math markup, posted below ---------- \starttext And this is some maths with PostScript fonts. \startformula {a \over b} = {c \over d} \iff ad - bc = 0, \qquad \int_0^{2\pi}\!\!\! \sin^2(x)dx =\pi, \qquad {\rm e}^{{\rm i}\pi} + 1 = 0, \qquad \sum_{k=1}^{\infty}{1 \over k^2} = {\pi^2 \over 6}. \stopformula Some ligatures: ffi, ffl. \stoptext ----------- When running "context test_math.tex", in the output file I don't see the "\iff" symbol. When running "texexec test_math.tex", everything is working fine. Any help would be appreciated, and sorry if this is a stupid question. Thank you, Andrei Dragomir