11.1 Subscripts

The Subscript

Subscript symbols are numerals, characters, or expressions that are positioned below the baseline. The rules governing the use of the subscript indicator, dots five six, differ slightly from the rules for the superscript indicator. In certain circumstances, in order to save space, the subscript indicator is not used.

Use of the subscript level indicator

The subscript level indicator must be used when a numeral, letter, or expression follows a baseline character. This is necessary in order to distinguish between characters on the baseline and those which are below the baseline.

The subscript level indicator is dots five six. The baseline indicator is a dot five.

Remember the numeric indicator is not used before a subscripted numeral since it is not the first item on a line or after a space.

Material subscripted to other subscripts

As with superscripts, the level of the subscripted material is indicated by the number of subscript level indicators that are used. Second order subscripts are positioned two levels below the baseline.

Subsequent levels would be shown with a corresponding number of subscript level indicators, following the same rules that are applied to superscripts. If a subscript of the second order is brought back to the level of the first order and not to the baseline, use a single subscript level indicator to return to the first order as in example 6.

Baseline indicator

When material following a subscripted item that requires the use of the subscript indicator is on the baseline, the baseline indicator must follow the subscript. The baseline indicator is not needed after a subscript that does not require the subscript indicator.

Non-use of the subscript indicator

When a plain letter or an abbreviated function name has a simple number as a subscript, the subscript indicator is not required.

All of the following conditions must be met in order to display a subscript without a subscript indicator:

  1. The baseline character must be a letter or an abbreviated function name; it cannot be a numeral.
  2. The subscript is a numeral which does not have a superscript or subscript of its own.
  3. The subscript must be a right subscripted numeral.
  4. A left subscripted numeral would require the subscript indicator.

Simultaneous superscripts and subscripts

In braille, if numerals, symbols, or expressions are shown with both a subscript and a superscript, the subscript is indicated first.

Left subscripts

A subscript may appear to the left of a baseline character.

In that case, the subscript indicator precedes the subscripted symbol. The baseline indicator follows the subscripted symbol and precedes the baseline character. When the subscript level indicator precedes a numeral, the numeric indicator is not required.

Example 1

x with subscript n
⠭⠰⠝

Example 2

two with subscript r
⠼⠆⠰⠗

Example 3

y with subscript three r
⠽⠰⠒⠗

Example 4

two with subscript three
⠼⠆⠰⠒

Example 5

n with first order subscript a and second order subscript b
⠝⠰⠁⠰⠰⠃

Example 6

three with first order subscript n subscript five plus three
⠼⠒⠰⠝⠰⠰⠢⠰⠬⠒

Example 7

x sub two minus x
⠭⠰⠆⠐⠤⠭

Example 8

a plain letter n with a subscript read as sub three
⠝⠒

Example 9

A capital b with a subscript one or B sub one
⠠⠃⠂

Example 10

In the chemical notation for carbon dioxide C O two
⠠⠉⠠⠕⠆

Example 11

subscripts within an expression do not require a subscript indicator or baseline indicator y sub one plus y sub two
⠽⠂⠬⠽⠆

Example 12

a sub one plus a sub two plus a sub three
⠁⠂⠬⠁⠆⠬⠁⠒

Example 13

log sub two of x equals seven
⠇⠕⠛⠆⠀⠭⠀⠨⠅⠀⠼⠶

Example 14

w sub n to the second
⠺⠰⠝⠘⠆

Example 15

n sub one to the second
⠝⠰⠂⠘⠆

Example 16

x as a left subscript of n
⠰⠭⠐⠝

Example 17

two as a left subscript of x
⠰⠆⠐⠭

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