This work is a collaboration between a mathematician (Pierre Portal) and a writer (T.R. Napper). It started with a question from Tim to Pierre: "In an alternative world, where technology is at medieval level, and mathematics is banned as a profane form of magic, how would a character with a secret knowledge of mathematics use it to defeat her enemies?"

 

Pierre explained how the Navier-Stokes equations - originally designed to describe the motion of fluids - has proven useful to model the motion of crowds in emergency situations. In the same way as this is used to inform building constructions, and reduce casualties in case of stampede, maybe this could be used in the opposite way: to maximise casualties in an enemy's stampede during a siege.

 

The next challenge was to find how knowledge of the Navier-Stokes equations could present itself in an imaginary world where none of our mathematical formalism exists. Tim asked about Eastern mathematics, Pierre explained the use of poetry in ancient Indian mathematics, as examples of advanced knowledge expressed in a fundamentally different way from that of modern mathematicians. As Tim's fictional world draws influences from medieval Japan, Pierre then wrote down the Navier-Stokes equations as a tanka (a traditional form of Japanese poetry). In Tim's upcoming book, the main character uses knowledge summarised by this poem to turn her city into a deadly trap for an invading army.

 

The work presented here is made of draft excerpts of Tim's upcoming book (featuring Pierre's poem), complemented by a drawing of the city turned into a trap by mathematics.