W-shingling
In natural language processing a w-shingling is a set of unique shingles each of which is composed of contiguous subsequences of tokens within a document, which can then be used to ascertain the similarity between documents. The symbol w denotes the quantity of tokens in each shingle selected, or solved for.
The document, "a rose is a rose is a rose" can therefore be maximally tokenized as follows:
The set of all contiguous sequences of 4 tokens isResemblance
For a given shingle size, the degree to which two documents A and B resemble each other can be expressed as the ratio of the magnitudes of their shinglings' intersection and union, or
where |A| is the size of set A. The resemblance is a number in the range , where 1 indicates that two documents are identical. This definition is identical with the Jaccard coefficient describing similarity and diversity of sample sets.
