Quantum State Discrimination with General Figures of Merit
  We solve the problem of quantum state discrimination with "general (symmetric) figures of merit" for an even number of symmetric quantum bits with use of the no-signaling principle. It turns out that conditional probability has the same form for any figure of merit. Optimal measurement and corresponding conditional probability are the same for any monotonous figure of merit. 
Won-Young Hwang, Yeong-Deok Han
quant-ph