What is the title of the course with Differential Geometry as a prerequisite?
SELECT title FROM course WHERE course_id IN (SELECT T1.course_id FROM prereq AS T1 JOIN course AS T2 ON T1.prereq_id  =  T2.course_id WHERE T2.title  =  'Differential Geometry')
SELECT title FROM course WHERE course_id IN (SELECT T1.course_id FROM prereq AS T1 JOIN course AS T2 ON T1.prereq_id  =  T2.course_id WHERE T2.title  =  'Differential Geometry')
[{'title': 'Cost Accounting'}, {'title': 'Systems Software'}, {'title': 'Environmental Law'}, {'title': 'International Practicum'}, {'title': 'Existentialism'}]