What is the main theme in the short story 'to da-duh, in memoriam'

Rivalry is an important theme. The story pits an aging Barbadian grandmother against her youthful American granddaughter. Upon their first meeting, the two sense a similarity in each other that far outweighs the differences presented by the seventy years between them. Most importantly, each has a stubborn strength of will and a confidence that her way of regarding the world is the right way.