Lesson 11.15: Type Faces
A variety of fonts may be used to represent mathematics in print. To represent a modification in the print font, the following braille indicators are placed before the letter, number, or symbol that is to be shown in the modified type-form. Type-form indicators have no print equivalent.
Dots four six and dots four five six may have different meanings when used in braille mathematics, depending upon placement of these symbols with respect to other symbols, and context.
Guidelines for using type-form indicators
Material displayed in alternative fonts does not always require the use of type-form indicators. If a particular font is consistently used throughout a text for letters, numerals, or other mathematical symbols, then the font is considered to be regular, not modified, and the type-form indicators are not used. For example, when variables in formulas are uniformly printed in an alternative font, such as boldface or italics, throughout a text, type-form indicators are not used. However, when an alternative font is used to convey a distinct mathematical meaning, then type-form indicators must be used. An example would be when different fonts are used to distinguish between two or more different meanings of the same letter, numeral, or symbol, or because the alternative font has mathematical significance.
Type-form indicators used with numerals
The numeric indicator is placed between a type-form indicator and a numeral or decimal point. The type-form indicator precedes the numeral being modified. When a sign of operation appears before a numeral and it is not in a different font, the type-form indicator appears after the sign and before the numeric indicator. If the sign of operation and the numeral are being modified in the same font, then the type-form indicator precedes the sign of operation.
Influence of type-form indicators with numerals
The type-form indicator's influence extends to the space following a numeral, or to a different type-form indicator representing another change in font.
A compound expression contains a numeral joined to a word or to an abbreviation by a hyphen. The following rules apply when brailling a compound expression.
If a numeral is in a regular font and there is a change after the hyphen to an alternative font, place the appropriate type-form indicator between the hyphen and the following symbol.
If a numeral in an alternative font is followed by a word or abbreviation in a different alternative font after the hyphen, the change occurs after the hyphen. Appropriate type-form indicators must be used before each part of the expression.
The use of the numeric indicator within a number indicates a change of font. When numerals or expressions contain some digits that are in an alternative form of type, or when there is more than one form of type within an expression, the appropriate type-form indicator and the numeric indicator must precede each change in type. When an alternative font, such as boldface, italics, script, or sanserif, is changed to a regular font within an expression, the numeric indicator precedes the numerals which are displayed in regular font.
The sanserif type-form indicator might be used, infrequently, to make a distinction between two letters. This distinction has mathematical significance; thus, the type-form indicator must be used.
Guidelines for using type-form indicators with letters
The type-form indicator must always be followed by an alphabetic indicator. An English letter is preceded by the English letter indicator, dots five six. If a letter is capitalized, the capitalization indicator is brailled after the letter indicator.
The script type-form indicator is used to denote letters which represent, for example, the set of real numbers, the set of rational numbers, or the set of integers. The Nemeth code uses the script indicator to denote these characters.
The influence of a type-form indicator extends only to the letter that immediately follows it. In a sequence of unspaced letters, a type-form indicator must precede each letter that is displayed in an alternative font.
Type-form indicators with labeled mathematical statements, words, and phrases
The following type-form indicators are used for labeled mathematical statements, words, and phrases.
- opening boldface type-form indicator, dots six, three, four five six
- closing boldface type-form indicator, dots four five six, six, three
- opening italic type-form indicator, dots six, three, four six
- closing italic type-form indicator, dots four six, six, three
- all capitals, dots six, six
These modifications make it possible to change the font of words and phrases by enclosing them within a set of opening and closing type-form indicators. A blank cell is inserted after the opening indicator and before the closing indicator.
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