1. A computerized method for evaluating a patent document, comprising: in a computer having a processor configured for: (a) introducing one or more patent indices, characterizing different aspects of the patent document and contributing to a quality of the patent document, the quality of the patent document being associated with a monetary value of the patent document; each index having a single numerical value and being defined on a bounded interval having respective minimal and maximal values; (b) performing a non-linear transformation of said patent indices into a Patent Quality (PQ) index, which characterizes the quality of the patent document by a single numerical value, said Patent Quality index being defined on a bounded interval for said Patent Quality index having respective PQ min and PQ max values; said transformation being continuous, monotonous with respect to each said one or more patent indices and being non-linear with respect to at least one of said one or more patent indices; wherein all patent indices are defined on the same bounded interval for each said patent index; wherein transforming any number of patent indices having equal numerical values holds the numerical value of said Patent Quality index unchanged; wherein said non-linear transformation has a parameter of non-linearity expressed as a real number, and wherein said non-linear transformation is a single-valued transformation providing a single numerical value for said PQ index for any parameter of non-linearity; and (c) analyzing numerical values of said patent indices by an Artificial Intelligence (AI) system, including generating a conclusion regarding the quality of the patent document based on numerical values of said patent indices and the performed analysis, and a reason explaining how the conclusion regarding the quality of the patent document relates to the numerical values of said patent indices.