Modification of description logic expressions

A method, executed by a computer system, for altering a base expression associated with an ontology, the method comprising the steps of:

• generating a canonical expression from the base expression;
• modifying the canonical expression to generate a modified canonical expression, the modification being the replacement of a target update expression segment in the canonical expression with a canonical source update expression segment generated from a source update expression segment;
• identifying a modification sub-expression within the canonical expression which includes one or more elements, and which includes the target update expression segment;
• modifying the base expression to generate a modified base expression by
• adding the modification sub-expression to the base expression to form an interim base expression;
• and
• replacing the target update expression segment with the source update expression segment in the interim base expression;
• generating a comparison canonical expression from the modified base expression;
• and
• comparing the comparison canonical expression with the modified canonical expression to determine whether to substitute the base expression with the modified based expression.

A computing system for altering a base expression associated with an ontology, the computing system including:

• a first expression expander for expanding a base expression into a canonical expression;
• a canonical expression modifier for modifying the canonical expression to generate a modified canonical expression, the modification being the addition, replacement or deletion of a target update expression segment;
• a base expression modifier for modifying the base expression to generate a modified base expression by adding a modification sub-expression to the base expression or deleting a modification sub-expression from the base expression, the modification sub-expression being determined in part from the target update expression segment;
• a second expression expander for expanding the modified base expression into a comparison canonical expression;
• and
• an expression comparator for comparing the comparison canonical expression with the modified canonical expression to determine whether to substitute the base expression with the modified base expression.