Kernel Contraction in EL

Belief contraction in description logics in a syntax-independent manner is an important and nontrivial problem for ontology management and DL communities. One approach for belief contractions is to take all minimal sets that imply a formula to be contracted and delete one formula from each est, which is also called kernel contraction. In this thesis we make an investigation of kernel contraction in the description logics EL. We demonstrate that kernel contraction in EL is rational by proving some of its properties. We present different ways to generating kernel contractions. We introduce some novel approaches such as localization and specificity to decide the preference between different certain kernel contractions by exploiting the structure of an EL knowledge base and we give algorithms for computing them.