Unit:
Κατεύθυνση / ειδίκευση Θεωρητική Πληροφορική (ΘΕΩ)Library of the School of Science
Author:
Συμεωνίδου Ιωάννα
Supervisors info:
Παναγιώτης Ροντογιάννης Αναπλ. Καθηγητής ΕΚΠΑ
Original Title:
Απειρότιμη Σημασιολογία και Στρωματοποίηση
Translated title:
Infinite-Valued Semantics and Stratification
Summary:
We study the behavior of infinite valued models, one of the most recent and
interesting extentions of the Well-Founded Semantics to disjunctive programs,
within the class of locally stratified programs. Its models belong to an
alternative logic with infinite truth values, which denote different degrees of
certainty regarding an atom’s logic value, ranging from absolutely true or
absolutely false to completely unknown. We show that minimal infinitevalued
models of locally stratified programs do not include the unknown truth value,
while the atoms of the lower strata are evaluated with greater certainty than
those of the higher strata. At the same time, we show the number of strata as
an upper bound of the multitude of distinct truth values appearing in its
minimal infinite-valued models. These models’structural relationship to
stratification is also reinforced by their property of maintainingminimality in
every subset of the program, defined by its stratification.
Keywords:
Disjunctive logic programming, Well-founded semantics, Infinite-valued semantics, Stratification, Local stratification
