The permanent versus determinant conjecture is a major problem in complexity theory that is equivalent to the separation of the complexity classes VDET and VNP.
Mulmuley and Sohoni (SIAM J Comput, 2008) suggested to study a strengthened version of this conjecture over the complex numbers and they provided an approach on how to solve the conjecture based on so-called occurrence obstructions.
We prove that this approach is impossible.