Still, since we're looking at math in fiction on this Website, I'll dwell on this point perhaps more than it deserves. For instance, let's consider the following passage:

I think it probably is true that some mathematicians prefer "pure mathematics", completely free of application. So, even if the word "whore" is a bit strong, the general sentiment is something that a relatively large minority of mathematicians might identify with. But, its purpose here is to reinforce the stereotype of a mathematician as being unconnected to the real world (both applied mathematics and his daughter). I'm a bit tired of this stereotype (can you tell?) and also tire of repeating that it is largely untrue.

So, instead, let me just say that when she uses mathematical terms, Whitty does a pretty good job of using them correctly (with "number plane" instead of "complex plane" being perhaps the only awkward phrase). And the story is well written, presenting a contrived scenario as a work of art to be studied for emotional potency and hidden symmetry. But, if you seek a story that gets somewhere or some insight into the world of mathematics, this is not the place to look.

BTW Visitors to this site might also be interested in "Darwin in Heaven", another (non-mathematical) story in the same collection in which Charles Darwin and Richard Feynman discuss evolution and theology in the afterlife.