docket number 40006173 titled u201c method of vector analysis for a document u201d assigned to the assignee of this document which is incorporated herein by reference the document segment vector projection block 18 calculates a projection value of each document segment vector onto the subspace let p n p n1 p n2 p nl t be a vector of s n after the projection the projection value p nm onto the m th basis vector can be given by the following equation the relatedness calculation block 19 calculates relatedness between each document segment and respective eigenconcept or basis vector the following is one of methods for calculating such relatedness an average and a standard deviation of the projection values onto the m th basis vector for all document segments can be obtained by the following equation p m average of the projection values onto the m th basis vector for all document segments u03c3 m standard deviation of the projection values onto the m th basis vector for all document segments let u03c0 nm be a variable indicating a positive relatedness of the n th document segment with the m th eigenconcept basis vector and let u03bd nm be a variable indicating a negative relatedness of the n th document segment with the m th eigenconcept basis vector these variables can be defined as follows p nm u2212 p m u03c3 m gt a then u03c0 nm 1 p nm u2212 p m u03c3 m lt b then u03bd nm 1 5 in the definition above a and b are predetermined threshold values assume a function h m n represents the extent.