Forbidden Configurations: Finding the number predicted by the   Anstee-Sali Conjecture is NP-hard
  Let F be a hypergraph and let forb(m,F) denote the maximum number of edges a hypergraph with m vertices can have if it doesn't contain F as a subhypergraph. A conjecture of Anstee and Sali predicts the asymptotic behaviour of forb(m,F) for fixed F. In this paper we prove that even finding this predicted asymptotic behaviour is an NP-hard problem, meaning that if the Anstee-Sali conjecture were true, finding the asymptotics of forb(m,F) would be NP-hard. 
Miguel Raggi
cs.DM math.CO