Kempe et al. [4] (KKT) showed the problem of influence maximization is NP-hard and a simple greedy algorithm guarantees the best possible approximation factor in PTIME. However, it has two major sources of inefficiency. First, finding the expected spread of a node set is #P-hard. Second, the basic greedy algorithm is quadratic in the number of nodes. The first source is tackled by estimating th...

This paper investigates the holdup problem in the dynamic search market where buyers and sellers search for their trading partners and specific investments are made after match but before trade. We show that frictionless (competitive) market imposes severe limitations on attainable efficiencies: Markets with small friction make the holdup problem more serious than those with large friction beca...