Vector spaces

Let be a vector space retrieval model embedded in . The set specifies the dimensions of the vector space V such that , and each object in is a vector in V. Formally, if , then < >. The function can be tfidf or one of its derivatives or a measure based on the distribution of tokens in the retrievable objects. The function can be equal to either the dot product measure or the cosine measure. Given an object , the function ranks an object on the basis of the similarity between < > and computed by .