Ensuring math mode


230 {<<#408#>math commands<#408#>>}

In LaTeX~2.09, if you wanted a command to work both in math mode and in text mode, the suggested method was to define something like: verbatim20 Unfortunately, the 231 stops 232 changing size correctly in (for instance) subscripts or a fraction. In LaTeX2e<#410#><#410#> you can define it thus: verbatim21 Now 233 will work correctly in all contexts. This is because the 234 does nothing, producing simply 235, when 236 is used within math mode; but it ensures that math mode is entered (and exited) as required when 237 is used in text mode.