A sublunar meteorological artist wakens from her memory recording to learn that a serial killer has been murdering her repeatedly, and is presumably still targeting her. In trying to comprehend what it means to be "herself" under these circumstances, she works out a four-dimensional metaphor for her various selves.

While I think this is a wonderful story, the "mathematics" of seeing a life as a 4-dimensional object is only mentioned in a few sentences, and (in my opinion anyway) isn't central to the story.