REL — a logic for relative evidential support
International Journal of Approximate Reasoning
A formal logic--588~ for Relative Evidential Support is proposed based on the following ideas: 1. Arguments are represented direct(y and are taken as the terms for ~5 °. By arguments we mean the relationships between two judgments expressing that one supports or refutes the other, ie, evidential supports; 2. Comparisons between arguments are used as carriers for their relative strengths. By comparisons we mean relationships between two arguments with respect to their strengths. 3. Uncertainty
... asoning is viewed as a process of three phases of." • evidence structure construction; • evidence accumulation; • decision-making. Some examples are presented showing how ~qZ~S: can be used to represent various kinds of uncertain information such as: • the relative strengths of evidential supports, eg, evidence e 1 supports conclusion PI better than evidence e 2 supports P2; • belief functions, eg. evidence e I is exhausted by stating a belief function with mass function m l; • necessity assertions, eg, the necessity function derived from the membership function f of predicate F on domain D; • probability assertions, eg, the probability that statement s is true is. 99. These examples illustrate the advantages off,S: over other representations of uncertain information and evidential reasoning, eg, 1. it is based on relative strengths of arguments that cannot be represented using any absolute measures; 2. It is capable of representing explicitly the design of evidence ; 3. It can represent many kinds of absolute measures--in doing so it has the merit 205 206 Z. Anet al. that it explicates the assumptions and requirements for using different kinds of measurements of uncertainty; 4. it provides a natural common base for a hybrid system. Our conclusion is that~qPS"S a is a suitable formalization for uncertain information.