Radha Mohan received her PhD from Purdue University in 1995. Her research interests are in commutative algebra. She is currently at St. Stephen's College, Delhi. Two ideas tha t pervade all of mathemat ics are equivalence, and the related notion of reduction. If an object in a given class can be carried into another by a transformation of a special kind, we say the two objects are equivalent. Reduct ion means the t ransformat ion of the object into an equivalent one with a special form as simple as possible.