Hospitality of Notation: Exam Techniques and Methods
When writing an exam answer on the Hospitality of Notation, you want to clearly define the concept and then structure the core techniques with sharp, precise examples. Examiners look for the distinction between hospitality in an array (horizontal/coordinate subjects) and a chain (vertical/hierarchical subjects).
Here is a streamlined, exam-focused version:
What is Hospitality of Notation?
In library classification, Hospitality is the ability of a notation system to accommodate newly emerging subjects in their correct logical positions without disturbing the existing sequence or forcing a renumbering of the entire scheme.
Main Methods for Achieving Hospitality
Classification schemes achieve hospitality across two dimensions: In Chain (hierarchical/vertical growth) and In Array (coordinate/horizontal growth).
1. Decimal Fraction Device (Hospitality in Chain)
This is the most common method used to extend hierarchical chains indefinitely. By treating numbers as decimal fractions rather than integers, new, more specific sub-topics can be added by appending digits to the end of an existing number.
- Example (DDC): 510 Mathematics → 516 Geometry → 516.3 Analytic Geometry.
2. Gap Device (Hospitality in Array)
The classification designer intentionally leaves blank spaces or vacant numbers within a sequence of coordinate topics to accommodate future subjects.
- Example: In DDC, numbers like 504 or 517 might be left unassigned so that a newly discovered branch of science can occupy that exact position later.
3. Sector Device (Hospitality in Array)
Introduced by S.R. Ranganathan in Colon Classification (CC), this method uses certain digits (like 9, z, or Z) strictly for their ordinal value, stripping them of their meaning. It turns a finite array into an infinite series of sectors.
- Example: 1, 2, 3… 8, 91, 92… 99, 991, 992… (Here, 9 is an empty digit used to start a new sector, allowing infinite extensions).
4. Emptying Digits (Hospitality in Array)
In this method, a specific digit (like T, V, or X in CC) is used to completely “empty” the semantic meaning of the digit preceding it, while retaining its original ordinal place. This allows the interpolation of brand-new main classes between two existing ones.
- Example: In CC, K stands for Zoology and L for Medicine. To insert Animal Husbandry between them without shifting L, the emptying digit X is used.
5. Empty-Emptying Digits (Hospitality in Array)
A further refinement where a digit (like U or W in CC) is both empty (has no meaning of its own) and emptying (robs the preceding digit of its meaning). This creates massive space for inserting clusters of new coordinate classes.
6. Synthesis Devices (Autonomy to Classifier)
These synthesis devices (Subject, Chronological, and Geographical) allow the cataloguer to independently create numbers for new subjects using existing facets, without waiting for a new printed edition of the classification scheme.
- Example (Chronological Device): Using the birth year of an author or the year a movement started to dynamically generate notation.