G. P. Zarri103The treatment of plane 2 in Figure 11 at the secondary indexes level will include:1. The insertion of a doublet—consisting of the date ‘1400’ and the address ofthe episode in the file of the biographical database proper—into the list of asecondary index corresponding to the 7th element of the ‘Montreuil’ matrix andthat of the ‘Col’ matrix of the primary indexes (BE-AFFECTED-BY + pos­teriority).
2. The insertion of a doublet—consisting of the date ‘1415’ and of the sameaddress in the biographical database—into the list corresponding to the 1stelement of the ‘Montreuil’ matrix (ditto ‘Col’) of the primary indexes (BEAFFECTED-BY + anteriority).
If plane 2 had included a date block, for example the first, characterized by a nondirect perspective, it would have been necessary to insert six doublets (three for‘Montreuil’ and three for ‘Col’) into the lists of the secondary indexes because eachof the dates constituting the fork, which has translated the non-direct perspective,would have given way to a doublet in the secondary lists addressed by the 8th (firstlimit of the fork) and 9th (second limit of the fork) elements of the ‘Montreuil’ (and‘Col’) matrix of the primary indexes.
3.22 The preselection algorithm (or rather the set of preselection algorithms) mustconfront very complex logical problems in order to finally isolate the doublets to beretained.
Indeed, it is not sufficient to affirm that a doublet whose first element specifies adate within the limits of the search interval will be selected. Categories and perspec­tives also have a role to play; to give just a very banal example, consider the codedepisode which translates the information ‘Robert de Bonnay was named bailiff ofMacon on 27th September 1413’, classed at the level of the secondary indexes in asingle list ‘direct perspective-posteriority’ (the date supplied in the filled date blockof the episode, which is accompanied by the thematic modulator ‘begin’, specifies,in effect, the beginning of a state). A search model of the type ‘Was Robert deBonnay bailiff of Macon in the period delimited by the years 1415-1420?’ will, ingeneral, have to select the doublet <date, address> corresponding to the aboveepisode, even if this date is outside the search interval specified by the model underscrutiny. Indeed, in the absence of data in the biographical base which explicitlyaffirm the opposite, it has to be supposed, conforming to the notion of ‘pos­teriority’, that Robert de Bonnay was still the bailiff during the years indicated bythe model.
It is not possible, given the length of this article, to give a detailed description ofthe preselection algorithms. I shall therefore restrict myself to presenting here, withthe help of Figure 14, an intuitive formulation of the algorithm which must beapplied in the case where there is no temporal modulator (begin, const, end) in thesearch model (see the model in Fig. 7), for example. The formal definition of thesealgorithms is given in Zarri et al. (1980: 54-70); details of their implementation inAPL are given in Zarri et al. (1981: 87-103).
In Figure 14, each ‘list’ is the symbolic representation of a secondary index, thatis, of a sequence of doublets <date, address>. The six lists represented correspond toa row of primary index: the list aDD is therefore the list ‘anteriority-direct perspec­tive’, the list aFl ‘anteriority-first limit of a fork’, the list cDD ‘contemporaneitydirect perspective’, etc. (see Fig. 13). The doublets of the secondary indexes are