Embodiments of the present invention provide for methods, systems and computer program products for utilizing a lattice structure in an advertisement serving system. The method according to one embodiment of the present invention comprises storing one or more advertisement contracts in a lattice structure. A request for one or more advertisements that satisfy one or more constraints is then received and within the lattice structure, a lowest level of one or more pools of advertisement contracts satisfying the one ore more constraints is located. A set of advertisement contracts is generated, wherein the set of advertisement contracts comprise one or more advertisement contracts from lowest level of the lattice structure. The method further comprises adding to the set of advertisement contracts advertisement contracts from the pools of advertisement contracts that are parent to the pools of contracts in the lowest level of the lattice structure.