The basic hypothesis made in this paper is that when a semantic category occurs in a text, the content words cooccurring in it are similar in terms of statistics.
本文的基本假设是：当这些词在文本中出现时，与它们前后同现的那些实词在统计意义上是相似的。
2
A single visit to a shop could be seen as a transaction, and all of the items bought in the course of this visit are then co-occurring and are called a market basket.
At the first interview, 10.4% of subjects had schizophrenia, bipolar disorder, or major depression only, and 9.4% had co-occurring mental disorders and substance dependence.