1. A method for segmenting a given input document, comprising: detecting terms that occur in said input document; segmenting said input document into document segments, each segment being an appropriately sized chunk; generating document segment vectors with as their elements the values related to the frequencies of said terms occurring in said document segments; calculating eigenvalues and eigenvectors of a square sum matrix of said document segment vectors; selecting a basis vector consisting a subspace from said eigenvectors to calculate the topic continuity of the document segments; calculating vectors with as the elements the values corresponding to the projection values of the each document segment vector onto said basis vectors; and determining segmentation points of said document based on the continuity of said projected vectors.