Universal  Decimal Classification
Notation A notation is a code commonly used in classification schemes to represent a class, i.e. a subject and its position in the hierarchy, to enable mechanical sorting and filing of subjects. UDC uses Arabic numerals arranged decimally. Every number is thought of as a decimal fraction with the initial decimal point omitted, which determines the filing order. An advantage of decimal notational systems is that they are infinitely extensible, and when new subdivisions are introduced, they need not disturb the existing allocation of numbers. For ease of reading, a UDC notation is usually punctuated after every third digit: →LIS Cafe-Home
Notation        Caption (Class description)
539.120           Theoretical problems of elementary particles physics. Theories and models of fundamental interactions
539.120.2        Symmetries of quantum physics
539.120.22      Conservation laws
539.120.222    Translations. Rotations
539.120.224    Reflection in time and space
539.120.226    Space-time symmetries
539.120.23      Internal symmetries
539.120.3        Currents
539.120.4        Unified field theories
539.120.5        Strings
Main classes
0	Science and Knowledge. Organization. Computer Science. Information Science. Documentation. Librarianship. Institutions. Publications
1	Philosophy. Psychology
2	Religion. Theology
3	Social Sciences
4	vacant
5	Mathematics. Natural Sciences
6	Applied Sciences. Medicine, Technology
7	The Arts. Entertainment. Sport
8	Linguistics. Literature
9	Geography. History
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 makes them stand out in complex expressions. Common auxiliary numbers always begin with a certain symbol known as a facet indicator, e.g. = (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. →LIS Cafe-Home
=... 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 →LIS Cafe-Home