the non-commuting graph $nabla(g)$ of a non-abelian group $g$ is defined as follows: its vertex set is $g-z(g)$ and two distinct vertices $x$ and $y$ are joined by an edge if and only if the commutator of $x$ and $y$ is not the identity. in this paper we 'll prove that if $g$ is a finite group with $nabla(g)congnabla(bs_{n})$, then $g cong bs_{n}$, where $bs_{n}$ is the symmetric group of degre...

The problem of determining key words and phases which best characterize a text document has important applications such as building a compact index for a largescale text processing system, or using a keyword set for summarization and topic detection. We approached this problem from two perspectives. Our knowledgepoor approach is based on statistical collocation detection using the t-test and li...

This paper presents a supervised approach for identifying generic noun phrases in context. Generic statements express rulelike knowledge about kinds or events. Therefore, their identification is important for the automatic construction of knowledge bases. In particular, the distinction between generic and non-generic statements is crucial for the correct encoding of generic and instance-level i...

This paper looks at the arguments for the stipulation that only heads are probes. Three areas where there traditionally have been made a difference between heads and phrases are examined. These areas are, phrase structure, movement, and selection. The strongest argument against probing phrases seems to be selection. Furthermore, Hallman’s (2004) suggestion to conflate selection and feature chec...

In this paper the suitability of different document representations for automatic document classification is compared, investigating a whole range of representations between bag-of-words and bag-of-phrases. We look at some of their statistical properties, and determine for each representation the optimal choice of classification parameters and the effect of Term Selection. Phrases are represent...

However, there are also many languages in which it is possible to have noun phrases in which there is no noun or pronoun, in which the only constituents of the noun phrase are words that otherwise occur as modifiers of nouns. For example, in the example in (1) from Nkore-Kiga, a Bantu language spoken in Uganda, the subject omuto ‘young’ is a word that normally functions in the language as an ad...

Most parsing algorithms require phrases that are to be combined to be either contiguous or marked as being ‘extraposed’. The assumption that phrases which are to be combined will be adjacent to one another supports rapid indexing mechanisms: the fact that in most languages items can turn up in unexpected locations cancels out much of the ensuing efficiency. The current paper shows how ‘out of p...

This paper describes experiments documenting significant variations in word usage patterns within social subgroups of AI researchers. As some phrases have very different collocational patterns than their constituent words, we look beyond occurrences of individual words, to consider word phrases. The mutual information statistic is used to measure the information content of phrases beyond that o...

Phrases are used in both commercial and experimental search engines. Despite the large amount of work in the area results remain mixed. It is still not clear whether phrases can be used to improve retrieval effectiveness. In this paper, we examine phrases and their properties independently of any specific retrieval approach. We explore phrase usage in text corpora and relevance patterns related...