Editing Universal Decimal Classification (section)

==== Common auxiliary tables ====
''Common auxiliaries'' are aspect-free concepts that can be used in combination with any other UDC code from the main classes or with other common auxiliaries. They have unique notational representations that make them stand out in complex expressions. Common auxiliary numbers always begin with a certain symbol known as a facet indicator, e.g. <nowiki>=</nowiki> (equal sign) always introduces concepts representing the language of a document; (0...) numbers enclosed in parentheses starting with zero always represent a concept designating document form. Thus (075) Textbook and =111 English can be combined to express, e.g.(075)=111 Textbooks in English, and when combined with numbers from the main UDC tables they can be used as follows: 2(075)=111 Religion textbooks in English, 51(075)=111 Mathematics textbooks in English etc.

*=...	Common auxiliaries of language. Table 1c
*(0...)	Common auxiliaries of form. Table 1d
*(1/9)	Common auxiliaries of place. Table 1e
*(=...)	Common auxiliaries of human ancestry, ethnic grouping and nationality. Table 1f
*"..."	Common auxiliaries of time. Table 1g helps to make minute division of time e.g.:  "1993-1996"
*-0...	Common auxiliaries of general characteristics: Properties, Materials, Relations/Processes and Persons. Table 1k.
*-02	Common auxiliaries of properties. Table 1k
*-03	Common auxiliaries of materials. Table 1k
*-04	Common auxiliaries of relations, processes and operations. Table 1k
*-05	Common auxiliaries of persons and personal characteristics. Table 1k this table is repeated