ISR11 Operating Instructions for the SMART Text Processing and Document Retrieval System chapter M. E. Lesk Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. 11-50 They retrieved data by computer techniques, They retrieved information by computer techniques. To match "They retrieved information by computer" but assign the output concept 301 to "information" instead of to "retrieved" one writes INFRET=301.2. (26)/(53,ll4)[OCRerr]3/l0 To define tree type 3 and the original tree simultaneously, one writes INFRET=30ID3( `V') (26)/13( `0') (53,ll[OCRerr])j[OCRerr]/l0, 3T1 5.1.6. Hierarchy The hierarchy is punched in a comparatively simple format. Each concept number is punched on a separate card, and represents a single node in the hierarchy. Indenting is used to indicate descent in the hierarchy. More exactly, the "level" of a node is defined as the number of the column on the IBM card in which the units digit of the concept number is punched. The parent of each node is defined as the last prece- ding node on a lower level, i.e. with its units digit punched further to the left. If a node is furnished with cross-references to other nodes, these are punched on the same card, to the right of the node number. There may be any number of cross-references, punched anywhere on the card (separated by blanks). All punching is restricted to columns 1-70. If additional space is needed, any character may be punched in column 72. This causes the next card to be interpreted as a continuation card. It is esthetically pleasing, although not necessary, to punch all brothers on the same level (in the same columns). For example, the following structure (with node number 2 cross referenced to node 7 and vice