# Accession Number:

## ADA301476

# Title:

## A Characterization of Probabilistic Entailment in Adams' Logic of Conditionals.

# Descriptive Note:

# Corporate Author:

## NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA

# Personal Author(s):

# Report Date:

## 1995-09-01

# Pagination or Media Count:

## 7.0

# Abstract:

Ernest Adams logic of conditionals is useful in expert systems because it can be used to reason about imperfect generalizations, i.e., generalizations of the form In nearly all instances where a is true, b is true. This paper defines a notion of importance and then shows that Adams logic is equivalent to a logic for reasoning about generalizations of the form in all important instances where a is true, b is true. A new method of proving results in Adams logic-a method based upon the importance notion-is described. This method of proof is often quite easy, particularly since Venn diagrams can be used to help find proofs. An example using this new method of proof is presented. The example shows that Adams logic justifies a common method of conflict resolution in expert systems, namely, the specificity-wins method. Finally, it is shown that Adams logic can be used to reason about a topic seemingly unrelated to imperfect generalizations the choices made by rational agents.

# Descriptors:

# Subject Categories:

- Theoretical Mathematics
- Cybernetics