We consider a project scheduling problem where the precedence constraints graph is an out-tree. The processing times can be compressed by using additional resources, which causes cost and simultaneously reduces the processing times of jobs. The objective is to minimize the sum of total lateness...

When scheduling a round robin tournament (RRT) a Home-Away-Pattern (HAP) set defines for each team i and each period p whether i plays at home or away in p. So far the complexity of the decision problem whether a RRT can be arranged based on a given HAP set or not is open. We give a necessary...

A single round robin tournament (RRT) consists of a set T of n teams (n even) and a set P of n - 1 periods. The teams have to be scheduled such that each team plays exactly once against each other team and such that each team plays exactly once per period. In order to establish fairness among...

A single round robin tournament (SRRT) consists of n teams and a set of periods. Matches between the teams have to be scheduled such that each team plays against each other team exactly once and each team plays at most once per period. In order to establish fairness among teams we consider a...

Single round robin tournaments are a well known class of sports leagues schedules. We consider leagues with a set T of n teams where n is even. Costs are associated to each possible match. Moreover, stadium availability, fixed matches, and regions' capacities are taken into account. The goal is...

Several types of constraints must be satisfied by schedules of real world sports leagues, e. g. stadium unavailability, fixed matches, forbidden matches, minimum number of breaks. Taking into account such constraints, determining a feasible schedule becomes a challenging task. Usually, there is...

In general scheduling a sports league is a difficult combinatorial optimization problem. We study some variants of round robin tournaments and analyze the relationship with the planar three index assignment problem. The complexity of scheduling a round robin tournaments is settled by a reduction...

A single round robin tournament can be described as a league of a set T of n teams (n even) to be scheduled such that each team plays exactly once against each other team and such that each team plays exactly once per period resulting in a set P of n — 1 periods. Matches are carried out at one...