1. A method for at least one computer to represent a knowledge base, comprising: at least one memory that stores a mapping of values to sets of evidences U in the knowledge base; executing by the at least one computer: creating objects in form E→A for the knowledge base, where A is a rule among rules in the knowledge base, and E is a subset of the sets of evidences U from the knowledge base that supports the rule A, so that the rule A is supportable by the set of evidences E; determining relationship constraints κ in form of set relations among a plurality of sets of evidences E; and computing for a target rule L, a first composite object ω 1 →G 1 →L 0 , the first composite object ω 1 constructed from a combination of the objects E→A to create a composite sets of evidences G 1 subject to the relationship constraints κ which support a composite rule L 0 , the composite rule L 0 being a combination of the rules implying the target rule L according to deductive reasoning indicated by the mapping of the values to the sets of evidences U, the first composite object ω 1 indicative according to the deductive reasoning of a first validity and/or a first plausibility value for the target rule L.