Some gastronomic thoughts on dual spaces

Extract

Some time ago, Geoffrey Matthews and others introduced the idea of ‘shopping’ matrices as a method of introducing matrix multiplication in schools, and it recently occurred to me that these shopping matrices might also provide a palatable realisation of something that undergraduates traditionally find pretty indigestible when they first meet it, namely the idea of dual space, and particularly the transpose or adjoint mapping associated with a given linear mapping between two vector spaces.