[NTG-context] fonts and function in math mode

Hi everyone, could you tell me how to use the Ubuntu font for the math command \max in the following example? \definefontfamily [mainface] [sans] [Ubuntu] [regularfont=ubuntu,italicfont=ubuntuitalic,boldfont=ubuntubold] \definefallbackfamily [mainface] [math] [Ubuntu] [preset=math:lowercaseitalic,tf=name:ubuntu] \definefontfamily [mainface] [math] [Latin Modern Math] \setupbodyfont[mainface] \starttext $ abc \max$ abc max \stoptext I am also interesting by knowing where I can find all the features "preset=math:" possible. Best regards, Flavien.