Unequal: The Math of When Things Do and Don’t Add Up

Mathematician Cheng attempts to impart crucial life lessons via the fundamentals of math in her uneven latest (after Is Maths Real?). The focus is on the meaning of “sameness” and “difference” in both equations and in life—Cheng defines sameness mathematically as when functions give exactly the same output when given an input. Explaining that “the point of math is to gain new understanding and illuminate different points of view,” Cheng posits that sameness is what “counts towards an equation being true,” while difference “is what counts towards it being interesting.” She draws direct parallels to society—mathematical symmetry is similar to reciprocity in human relationships, for example—and she makes a case that using the ways of thinking required in math can enrich people’s lives and provide a more nuanced viewpoint. Things get complicated in her survey’s second half, however, when Cheng veers into an extended discussion of category theory, the abstract branch of mathematics that focuses on structures and their relationships. Only readers committed to a deep dive into mathematical arcana will be able to make sense of the connections she draws between complex equations and society. This one doesn’t quite come together. Agent: George Lucas, InkWell Management. (Sept.)