Reply To: subscripts
Is Rule XIII Sec. 77 what you are looking for?
The subscript indicator must not be used to indicate a numeric subscript provided that all of the following conditions hold:
i. The corresponding numeric sign must be a right, and not a left, subscript.
ii. The corresponding numeric sign must be subscript of first order, and not of higher order.
iii. The sign with which the numeric subscript is associated must be an abbreviated function name (log2) or a letter which has a separate identity. In the latter case, this letter must not be any letter which represents a numeral in a non-decimal base. Otherwise, the letter may be from any alphabet and in any type form, and may be modified by one or more primes or a superscript. In the case of a two-letter abbreviation for a chemical compound, the abbreviation must be treated as if it were a letter.
iv. The subscript must consist of numeric symbols only, and must carry no superscripts or subscripts of its own.
edited by CrepeMyrtle on 6/9/2011