I get the same error on mac os x 10.11.6 using this document. but $a\Longrightarrow b$ gives the wanted symbol
Bjarnþór > On 8. jan. 2017, at 17:35, Paul A. Rubin <parubi...@gmail.com> wrote: > > I just encountered something goofy, and I'm not sure if it's a LyX bug or > something odd about what's installed on my system. When I try to compile the > attached document (LyX 2.2.2, Linux Mint 18.1, TeXLive) I'm told that > \implies is an undefined control sequence. Looking at the source window, LyX > is not loading any math-related packages. If I go into document settings and > change amsmath from "load automatically" to "load always", things work. > > To be honest, I'm not sure what LaTeX packages provide \implies. If in fact > it's not in base LaTeX, shouldn't LyX recognize that it requires amsmath? > > I don't recall encountering this before, so I'm guessing that I'm missing a > TeXLive package, but I have no idea which. > > Paul > > <implies.lyx> ------------------------------------------------------------------------------------------------- Bjarnþór G. Kolbeins sími: 431-2579 GSM: 860-2579 bgkolbe...@gmail.com