Ritu Chadha
Member of technical staff, Bell Communications Research

While the title of Ritu Chadha's doctoral dissertation is daunting - Applications of Unskolemization - the ramifications of that research are far reaching. Unskolemization is the process of replacing certain functions by existentially quantified variables in logic formulas, which is useful for deducing facts about collections of logical formulas. As a doctoral student at the University of North Carolina at Chapel Hill, she developed an algorithm for performing unskolemization and applied it to several areas, including the automation of program verification.

``The foremost problem in software development today is ensuring the correctness of software,'' according to Chadha. Much research has been devoted to mechanizing the verification process, but no one had been able to devise a general method for mechanically deriving program loop invariants - until Chadha developed an algorithm based on her thesis work. This opens up the possibility of building systems that will mechanically prove the correctness of software. ``There is still a lot of work to be done to make such systems commercially viable,'' she said, but this could dramatically cut the cost of software development since laboratories typically budget as much as 50 percent of their cost for software testing.

She also applied her thesis to machine learning, developing another algorithm based on unskolemization that deduces certain facts about collections of objects or statements. For example, given examples of a class of objects, the algorithm can generate a general description of objects in that class. This method can be applied in program verification as well as other fields.

Chadha spent most of her adolescent years in a highly respected high school for girls in India. The teachers (all female) warned the students that science and math were not ``for girls.'' While she believes this discouraged many talented girls, she persisted, going on to major in mathematics at Delhi University and earn the highest grades ever obtained there in any subject. During her undergraduate and graduate school years, Chadha never encountered any discrimination due to gender. However, the disproportionate male-female ratio in computer science departments did make it difficult for her to interact socially with students.

Suggestions:

1. Don't lose confidence in yourself despite any discouragement or discrimination you may encounter.
2. Never think in terms of gender where work and ability are concerned.
3. Don't be afraid to point out any discrimination if and when you encounter it.
4. Companies with multiple locations should be sensitive to the ``two-body problem'' (where both members of a couple need to work) and facilitate internal transfers for employees in such situations.