Here are some quotes from the story so you can get the flavor of its mathematical jargon:

I found this interesting since I do generally consider time to be a complex parameter in my mathematical physics research (it makes things much nicer from a purely mathematical, formal point of view!). However, I don't think there is really any way to make sense of what he says in the story about all of this...and it's besides the point anyway. All of this was just a way of convincing the reader that such travel between "the three universes" is possible so that you can follow with interest what happens to the evil dictator...and since it is not at all mathematical I won't give away the ending by telling you here what does happen to him.

No! Actually, Mr. Day, you were the first person to write to me about it. Since then, I have actually gotten hold of (a very poor) copy of the story, but I would be grateful for a cleaner copy if anyone is able to get me one!

Note that in its original printing, the title of the story had a mathematical misprint. As you probably know, x^1/3 is the same as "the cube root of x" (because x^1/3*x^1/3*x^1/3=x^1/3+1/3+1/3=x). Another way to write "the cube root of x" is to put a little "3" in the crook of a radical (square root sign). In the title of this story, apparently confusing the two, they put a 1/3 in the crook of the radical! Also, I'd like to point out that the solution to a cubic equation is not necessarily called a "cube root", so the title is not actually well justified by the description of the cubic equation. Moreover, let me point out that here, once again, we see scientists dealing with what is apparently a polynomial equation in one variable. This is, I believe, much more common in fiction than in reality. More likely, whatever equation describes these situations is a partial differential equation. But then the author would not be able to refer to "the three roots" that every cubic equation has.