Web Based System for Weighted Defeasible Argumentation

Abstract

In a previous work we defined a recursive semantics for reasoning about which arguments should be warranted when extending Defeasible Argumentation with defeasibility levels for arguments. Our approach is based on a general notion of collective conflict among arguments and on the fact that if an argument is warranted it must be that all its sub-arguments also are warranted. An output of a program is a pair consisting of a set of warranted and a set of blocked arguments with maximum strength. Arguments that are neither warranted nor blocked correspond to rejected arguments. On this recursive semantics a program may have multiple outputs in case of circular definitions of conflicts among arguments and for these circular definitions of conflicts we define what output, called maximal ideal output, should be considered based on the claim that if an argument is excluded from an output, then all the arguments built on top of it should also be excluded from that output. In this paper we show a web based system we have designed and implemented to compute the output for programs with single and multiple outputs. For programs with multiple outputs the system also computes the maximal ideal output. An interesting feature of the system is that it provides not only both sets of warranted an blocked arguments with maximum strength but also useful information that allows to better understand why an argument is either warranted, blocked or rejected. © 2013 Springer-Verlag.