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. 11-49 even if the integer was previously in use to identify another tree; the old tree is lost in this case. If the letter "P" is used, in addition to specifying a definition valid for this run, a deck of binary cards is also punched which may later be added to the deck of the subprogram TRECND in link 102 to permanently alter the standard tree types. The "T" or "P" should be followed by a set of integers, separated by cozmnas, which identify the `1key11 nodes of the new tree type. Usually there is only one key node. e) the following additional fonnat requirements should be noted. Blanks are completely forbidden except in the BCD name field. The occurrence of a blank ends the definition. To continue a definition from one card to the next, a minus sign (-) should be punched as the last non-blank character of the first card, and the next card should be started with five blanks and an asterisk in columns 1-6. Punching of the tree definition should be resumed in column 7. Consider the follcwing examples. Assume that "information1t is represented by concept 114, "data" by 53, "retrieval" 26, and t1information retrieval" is to be defined concept 301. Note that tree type 1 is : l?'E and type 3 is: 26 (V) l[OCRerr][OCRerr][OCRerr]O2 ([OCRerr] To define tree type 3, one could write: TYPE3 D3( `V')/13( `[OCRerr]`)//[OCRerr]3Tl and to define type 1: *£xk'[OCRerr]l /I[OCRerr]ITl This tree would match all the following sentences if the appropriate concept numbers are assigned to the nodes (nun[OCRerr]bering the trees 10 and ll, and naming them INFRET): INFRET=30l(26)/(53,l14)[OCRerr]l/l0, 3+ Infoz[OCRerr]nation retrieval is useful, Data retrieval is useful,