Watching the marvelous Broadway revival of Tom Stoppard’s 1993 play Arcadia recently, we were struck by the Thomasina character’s interest in Fermat’s Last Theorem. Stieg Larsson fans will recall that the pursuit of Fermat’s Last Theorem is also a running theme in The Girl Who Played with Fire, as Lisbeth Salander shows readers a few flashes of her mathematical genius, solving this now three centuries old enigma in her down time away from the breakneck pace of the plot’s murderous details.
Stoppard’s Thomasina character is in her mid-teens during the action of the play (similar in age to Lisbeth when she tried to kill her father and ended up imprisoned in the mental hospital). Stoppard seems to have modeled Thomasina at least partially on Lord Byron’s brilliant daughter Ada, who is known to have worked with Charles Babbage in pioneering the earliest 19th century ideas about computers and programming). Set in the early 19th century, Arcadia depicts a Thomasina who is fascinated with what is then only a century and a half old enigma of Fermat’s Last Theorem. (Interestingly, in the last few decades, growing attention has focused on the work of Sophie Germain, a French female mathematician who was working on the Fermat problem at the time the Arcadia play is set).
Common to Stoppard and Larsson’s visions is a metaphor about certainty and knowability. The fact that Fermat never gave his proof, but only scribbled an enigmatic note to the effect that there was not enough room in the book he was writing in to demonstrate the proof, is important in both stories. Thomasina, Lisbeth (and Ada, Byron’s daughter, in real life) are all young females with inspired brilliance in multiple fields, struggling to find their place in male dominated societies. Math experts have noted that Larsson’s portrayal of how Lisbeth solves the Fermat enigma are not close to accurate, nor are his comments about Andrew Wiles, who is widely credited with the late 20thcentury solution to the Fermat enigma. But at the level of metaphor, Fermat is important to the overall story Larsson is trying to tell. There are many good discussions of Fermat’s Last Theorem and Lisbeth Salander online. This one is particularly interesting.