According to Wikipedia:

A set of dice is **nontransitive** if it
contains three dice, *A*, *B*, and *C*, with the
property that *A* rolls
higher than *B* more than
half the time,

and *B* rolls
higher than *C* more than
half the time, but it's not true that *A* rolls
higher than *C* more than
half the time.

In other words, a set of dice is nontransitive if its "rolls
a higher number than more than half the time" relation is not transitive.

As such .. this is a math effect