Handling Errors in Mathematical Formulas

In tutorial systems, effective progress in teaching the problem-solving target is frequently hindered by expressive sloppiness and low-level errors made by the student, especially in conventionalized expressions such as formulas. In order to improve the effectiveness of tutorial systems in teaching higher-level skills, we present a fault-tolerant formula interpreter that aims at finding plausibly intended, formally correct specifications from student statements containing formal inaccuracies. The interpretation consists of local changes based on categorization of errors, a fault-tolerant structure building, and testing contextually-motivated alternations. The error interpretation component is intended to enhance the analysis component of a tutorial system that teaches mathematical proving skills.