Question
Consider the following snapshot of a system running n processes. Process i is holding xi instances of a resource R, for 1 ≤i≤n. Courrently, all instances of R are occupied. Further, for all i, process i has placed a request for an additional yi instances while holding the xi instances it already has. There are exactly two processes p and q such that yp=yq=0. Which one of the following can serve as a necessary condition to guarantee that the system is not approaching a deadlock?