On the Synthetic Factorization of Projectively Invariant Polynomials

We prove that, after multiplication with a suitable monomial, every homogeneous bracket polynomial of rank r>=3 can be factored into a meet and join expression in the Cayley algebra. The main tool in our construction is an explicit algorithm for rewriting polynomial functions in terms of synthetic constructions in projective geometry. We also discuss applications of Cayley factorization to automated geometry theorem proving.