(which thereby also determine the information content of particular scenes).

The relationship between scenes and words in Figure 1 is ultimately given by the *dual space* relationships (Murtagh 2005): each scene is located at the center of gravity of all words; and each word is located at the center of gravity of all scenes. As noted above, this establishes a semantic property for the location of any scene - since the scene's location is determined by the word set.

Similarly each word's location is determined by the scene set, hence establishing its semantics.

In practice, Figure 1 presents a very useful view of relationships in our scenes
× words data. We can look for polarities in the data; or anomalous scenes or words; or clusters or other configurations of scenes with reference to words or vice versa. But it is an approximation to the full dimensional reality. Therefore for some purposes, as in the case of the next section, we prefer to use the full dimensionality Euclidean representation furnished by the factor space. In such a case there is no low dimensional projection involved, and no loss of information.

## 2.2 Selecting The Most Pertinent Terms

Presenting a result with around 1700 terms (cf. Figure 1) does not lend itself to convenient display. We ask therefore what the most useful - perhaps the most discriminating terms - are. In Correspondence Analysis both texts and their characterizing terms are projected into the same factor space. So, from the factor coordinates, we can easily find the closest term(s) to a given text. We do this for each of the 50 scenes and find - in the full dimensionality factor space, and so with no approximation involved - the following for the 50 scenes in succession in program CSI 101: "royce" "soon" "coughs" "tape" "building" "makes" "gasps" "shift" "sign"
"forced" "rushes" "city" "feet" "body" "hotel" "ah" "trying" "or" "business"
"shoes" "screaming" "swab" "gun" "were" "rattle" "print" "really" "brass"
"remember" "judge" "any" "latex" "skin" "both" "herself" "believe" "hospital" "dress" "finger" "minute" "deep" "statement" "minutes" "shh" "match"
"second" "watching" "enters" "ring" "full" Among these terms, each individually characterizing a scene, in succession, we note the following. "Royce" is a personal name. Terms like "Ah" and "Shh" are present, and reflective of the scenes. We experimented with other alternatives, such as selecting the more important scenes - which, from our procedure, leads also to the more important words - on the basis of totalled high frequency of occurrence. This did not lead to a more attractive word set (e.g. nouns or verbs). Finally, we decided to limit ourselves to just one nearest neighbor word for each scene on the grounds of facilitating interpretation. However nothing restricts the consideration of, for example, 3 or 4 nearest neighbors.

In the following, in all cases, we use the first nearest neighbor word of each of the scenes. We also discuss the use of a restricted set of words in section 3.2.