15.  Braces for Grouping

      Normally, the end of a subscript or superscript is marked simply by a blank (or tab or tilde, etc.) What if the subscript or superscript is something that has to be typed with blanks in it? In that case, you can use the braces { and } to mark the beginning and end of the subscript or superscript: e sup {i omega t}
is

Rule: Braces can always be used to force EQN to treat something as a unit, or just to make your intent perfectly clear. Thus: x sub {i sub 1} sup 2
is

with braces, but x sub i sub 1 sup 2
is

which is rather different.

      Braces can occur within braces if necessary: e sup {i pi sup {rho +1}}
is

The general rule is that anywhere you could use some single thing like x, you can use an arbitrarily complicated thing if you enclose it in braces. EQN will look after all the details of positioning it and making it the right size.

      In all cases, make sure you have the right number of braces. Leaving one out or adding an extra will cause EQN to complain bitterly.

      Occasionally you will have to print braces. To do this, enclose them in double quotes, like "{". Quoting is discussed in more detail in section 14.